Diimines and secondary diamines

ABSTRACT

This invention provides aromatic diimines which have imino hydrocarbylidene groups with at least two carbon atoms, and aromatic secondary diamines which have amino hydrocarbyl groups with at least two carbon atoms. Both the aromatic diimines and the aromatic secondary diamines either are in the form of one phenyl ring, or are in the form of two phenyl rings connected by an alkylene bridge; each position ortho to an imino group or an amino group bears a hydrocarbyl group. When in the form of one phenyl ring, there are two imino groups on the ring or two amino groups on the ring; the imino groups or amino groups are meta or para relative to each other. When in the form of two phenyl rings connected by an alkylene bridge, there is either one imino group or one amino group on each phenyl ring. Also provided are processes for forming diimines and secondary diamines.

REFERENCE TO RELATED APPLICATION

This application claims the benefit and priority of U.S. ProvisionalApplication No. 60/665,915, filed Mar. 28, 2005, the disclosure of whichis incorporated herein by reference.

TECHNICAL FIELD

This invention relates to the preparation of diimines and secondarydiamines from primary diamines, and to new aromatic diimines and newaromatic secondary diamines.

BACKGROUND

There are many polyfunctional compounds, including diols and aromaticdiamines, which are indicated to be useful as chain extenders in thepreparation of polyurethane, polyurea, and polyurethane-urea polymersand/or as curing agents for epoxy resins. None of these compounds has areactivity such as to make it universally ideal, and many fail toprovide satisfactory properties in the products made by their use. Thus,there is still a need to find new compounds capable of serving as chainextenders or curing agents. U.S. Pat. No. 4,806,616 teaches the use ofcertain N,N′-dialkylphenylenediamines as chain extenders in preparingpolyurethanes and polyureas. In this connection, also see for exampleU.S. Pat. No. 4,528,363, which teaches the use of secondary aliphaticdiamines as part of a resin binder, and U.S. Pat. No. 6,218,480 B1,which discloses use of aromatic diamines as hardeners for polyurethanes.Secondary aromatic diamines have also been used as anti-degradants forrubber; see U.S. Pat. No. 4,900,868.

Imines are often formed from combination of a primary amine and analdehyde or ketone. Such imines can be used as flavors (see U.S. Pat.No. 3,625,710) or fragrances (see EP 1067116).

To date, it has not been found possible to obtain aromatic diimineshaving groups with two or more carbon atoms from aromatic primarydiamines where the two amino groups are either on one phenyl ring, orone amino group is on each of two phenyl rings, where the two phenylrings are connected via an alkylene bridge, and in which each positionortho (immediately adjacent) to each amino group bears a hydrocarbylsubstituent. Attempts to prepare diimines via reaction of such primarydiamines with acetaldehyde or acetone in the presence or absence ofcatalysts have not worked; see U.S. Pat. Nos. 5,041,668 and 5,008,453.It had been indicated that the presence of an aryl group on the nitrogenor carbon of an imine group stabilized the imine; however, it has beenreported that at least some of the compounds previously believed to bestable aromatic imines had been misidentified and were really polymersformed from unstable imines. In this connection, see Distefano et al.,J. Chem. Soc. Perkin Trans. II, 1985, pp. 1623-1627.

It would be desirable to have routes to such diimines, and to haveroutes to aromatic secondary diamines that can be obtained from suchdiimines. There is a growing need for chain extenders with slower curerates, so it would be a further advantage if these aromatic secondarydiamines exhibited slower curing rates than those of presently availablechain extenders.

SUMMARY OF INVENTION

This invention in part provides processes for preparing diimines inwhich the imino hydrocarbylidene groups have at least two carbon atoms,where the diimine is (a) an aromatic diimine which is either in the formof one phenyl ring having two imino groups on the ring, in which eachposition ortho to an imino group (—N═R) bears a hydrocarbyl group, or inthe form of two phenyl rings connected by an alkylene bridge and havingone imino group on each ring, in which each position ortho to an iminogroup bears a hydrocarbyl group, (b) an aromatic diimine in which atleast one position ortho to each imino group has a hydrogen atom as asubstituent, and which aromatic diimine is either in the form of onephenyl ring having two imino groups on the ring or in the form of twophenyl rings connected by an alkylene bridge and having one imino groupon each ring, or (c) an aliphatic diimine, where the diimine is made byreacting a primary diamine with at least one ketone and/or aldehyde. Theart teaches that diimines of type (a) could not be made. These aromaticdiimines, which surprisingly can be made, are compositions of theinvention. Aromatic secondary diamines made from aromatic diimines oftype (a) are also compositions of the invention. Surprisingly, sucharomatic secondary diamines exhibit slower curing rates than those ofpresently available chain extenders. Slower cure rates are desirable forcertain proprietary commercial applications. By hydrogenating (reducing)aromatic diimines of type (a), the corresponding novel aromaticsecondary diamines of the invention are formed. Processes for formingsecondary diamines, including the aromatic secondary diamines that arecompositions of the invention, from primary diamines in one step arealso provided by this invention. In all of the processes of thisinvention, relatively mild pressure and temperature conditions are used;advantageously, ordinary process apparatus can be employed, so there isno need for specialized equipment, such as that required forhigh-pressure reactions. This is of particular significance in processeswhere hydrogen gas is employed in the formation of secondary diamines.The process technology of this invention can be used to prepare a widevariety of known diimines and secondary diamines via reaction of primarydiamines with ketones or aldehydes.

One embodiment of this invention provides, as new compositions ofmatter, aromatic diimines wherein each imino group (—N═R) has at leasttwo carbon atoms, and wherein the diimine either is in the form of onephenyl ring having two imino groups on the ring, which imino groups aremeta or para relative to each other, and in which each position ortho toan imino group bears a hydrocarbyl group, or is in the form of twophenyl rings connected by an alkylene bridge and having one imino groupon each ring, and in which each position ortho to an imino group bears ahydrocarbyl group. The aromatic diimines of the invention can berepresented by the structures:

where each R^(a) may be the same or different, and each R^(a) is ahydrocarbyl group, R^(b) is an alkylene bridge, and each R^(c) is ahydrocarbylidene group having at least two carbon atoms.

Another embodiment of this invention provides, as new compositions ofmatter, aromatic secondary diamines wherein each amino group (—NHR) hasat least two carbon atoms, and wherein the secondary diamine either isin the form of one phenyl ring having two amino groups on the ring,which amino groups are meta or para relative to each other, and in whicheach position ortho to an amino group bears a hydrocarbyl group, or isin the form of two phenyl rings connected by an alkylene bridge andhaving one amino group on each ring, and in which each position ortho toan amino group bears a hydrocarbyl group. The aromatic diamines of theinvention can be represented by the structures:

where each R^(a) may be the same or different, and each R^(a) is ahydrocarbyl group, R^(b) is an alkylene bridge, and each R^(d) is ahydrocarbyl group having at least two carbon atoms.

Another embodiment of this invention is a process for forming asecondary diamine. The process comprises mixing together at least oneketone or aldehyde, at least one acid ion exchange resin, at least onehydrogenation agent, and at least one primary diamine, such that asecondary diamine is formed. The primary diamine is I) an aromaticprimary diamine in which at least one position ortho to each amino grouphas a hydrogen atom as a substituent, and which aromatic primary diamineis either in the form of one phenyl ring having two amino groups on thering or in the form of two phenyl rings connected by an alkylene bridgeand having one amino group on each ring, or II) an aromatic primarydiamine in which each position ortho to an amino group bears ahydrocarbyl group, and which aromatic primary diamine is either in theform of one phenyl ring having two amino groups on the ring, which aminogroups are meta or para relative to each other or is in the form of twophenyl rings connected by an alkylene bridge and having one amino groupon each ring, or III) an aliphatic primary diamine. When the primarydiamine is I), the hydrogenation agent is a hydride transfer agent, adissolving metal reagent, a borane reductant, or hydrogen with ahydrogenation catalyst, where the hydrogenation catalyst is sulfidedplatinum on carbon, sulfided palladium on carbon, or a mixture thereof.When the primary diamine is II), the hydrogenation agent is a dissolvingmetal reagent or hydrogen with a hydrogenation catalyst, where thehydrogenation catalyst is sulfided platinum on carbon, sulfidedpalladium on carbon, or a mixture thereof, or is selected from the groupconsisting of palladium on carbon, platinum on carbon, and a mixture ofboth of these, when used with hydrogen sulfide or at least one strongacid. When the primary diamine is III), the hydrogenation agent is ahydride transfer agent, a dissolving metal reagent, a borane reductant,or hydrogen with a hydrogenation catalyst, where the hydrogenationcatalyst is sulfided platinum on carbon, sulfided palladium on carbon,or a mixture thereof.

Still another embodiment of this invention is a process for forming adiimine. The process comprises mixing together at least one ketone oraldehyde, at least one acid ion exchange resin, and at least one primarydiamine, such that a diimine is formed. The primary diamine is I) anaromatic primary diamine in which at least one position ortho to eachamino group has a hydrogen atom as a substituent, and which aromaticprimary diamine is either in the form of one phenyl ring having twoamino groups on the ring or in the form of two phenyl rings connected byan alkylene bridge and having one amino group on each ring, or II) anaromatic primary diamine in which each position ortho to an amino groupbears a hydrocarbyl group, and which aromatic primary diamine is eitherin the form of one phenyl ring having two amino groups on the ring,which amino groups are meta or para relative to each other or is in theform of two phenyl rings connected by an alkylene bridge and having oneamino group on each ring, or III) an aliphatic primary diamine. Oftenthis process further comprises mixing together at least a portion of thediimine and a hydrogenation agent. When the primary diamine used informing the diimine is I) or III), the hydrogenation agent is a hydridetransfer agent, a dissolving metal reagent, a borane reductant, orhydrogen with a hydrogenation catalyst, wherein the hydrogenationcatalyst is sulfided platinum on carbon, sulfided palladium on carbon,or a mixture thereof. When the primary diamine used in forming thediimine is II), the hydrogenation agent is a dissolving metal reagent orhydrogen with a hydrogenation catalyst, where the hydrogenation catalystis sulfided platinum on carbon, sulfided palladium on carbon, or amixture thereof, or is selected from the group consisting of palladiumon carbon, platinum on carbon, and a mixture of both of these, when usedwith hydrogen sulfide or at least one strong acid, such that a secondarydiamine is formed.

Another embodiment of this invention is a process for forming anaromatic secondary diamine. The process comprises mixing together atleast one ketone or aldehyde, hydrogen, a hydrogenation catalystselected from sulfided platinum on carbon, sulfided palladium on carbon,and a mixture thereof, and at least one primary diamine, such that asecondary diamine is formed. When the primary diamine is I) an aromaticprimary diamine in which at least one position ortho to each amino grouphas a hydrogen atom as a substituent, and which aromatic primary diamineis either in the form of one phenyl ring having two amino groups on thering or in the form of two phenyl rings connected by an alkylene bridgeand having one amino group on each ring, the process is conducted at atemperature in the range of about 20° C. to about 120° C. and at ahydrogen pressure in the range of about 14 to about 125 pounds persquare inch. When the primary diamine is II) an aromatic primary diaminein which each position ortho to an amino group bears a hydrocarbylgroup, and which aromatic primary diamine is either in the form of onephenyl ring having two amino groups on the ring, which amino groups aremeta or para relative to each other or is in the form of two phenylrings connected by an alkylene bridge and having one amino group on eachring, the process is conducted at a temperature in the range of about75° C. to about 140° C. and at a hydrogen pressure in the range of about14 to about 150 pounds per square inch. When the primary diamine is III)an aliphatic primary diamine, the process is conducted at a temperaturein the range of about 20° C. to about 140° C. and at a hydrogen pressurein the range of about 14 to about 150 pounds per square inch.

A further embodiment of the invention is a formulation which is formedfrom ingredients comprising at least one polyol and/or at least onepolyetheramine, at least one isocyanate, and at least one aromaticsecondary diamine. The aromatic secondary diamine is at least one of thearomatic secondary diamines described above as new compositions ofmatter.

A still further embodiment of the invention is a method for producing apolyurethane, polyurea, or polyurea-urethane. The method comprisesblending at least one polyol and/or at least one polyetheramine, atleast one isocyanate, and at least one aromatic secondary diamine. Thearomatic secondary diamine is at least one of the aromatic secondarydiamines described above as new compositions of matter.

These and other embodiments and features of this invention will be stillfurther apparent from the ensuing description and appended claims.

FURTHER DETAILED DESCRIPTION OF THE INVENTION

Certain terms that are commonly used in the art can be used to refer tovarious aspects of the present invention. Imines that are products of areaction of a primary amine and a carbonyl compound are sometimes calledSchiff bases, and such imines are formed by at least some of theprocesses of the invention. When the carbonyl compound used to form theimine is a ketone, such an imine is occasionally referred to as aketimine; similarly, when the carbonyl compound used to form the imineis an aldehyde, such an imine is occasionally referred to as analdimine. The formation of a secondary amine from a primary amine and analdehyde or ketone is often referred to as reductive alkylation orreductive amination, and the terms “reductive alkylation” and “reductiveamination” can be used to describe some of the processes of theinvention.

Those of skill in the art will recognize that there are several ways toname the aromatic primary diamines used in the processes of theinvention, as well as the aromatic diimines and the aromatic secondarydiamines that are compositions of the invention. For example, thestructure

which represents a particularly preferred aromatic primary diamine inthe processes of the invention, can be called2,4-diethyl-6-methyl-1,3-benzenediamine,2,4-diethyl-6-methyl-1,3-phenylenediamine,3,5-diethyl-2,4-diaminotoluene, or 3,5-diethyl-toluene-2,4-diamine.Similarly, the structure

which represents another particularly preferred aromatic primary diaminein the processes of the invention, can be called4,4′-methylenbis(2,6-diethylbenzeneamine),4,4′-methylenbis(2,6-diethylaniline), or3,3′,5,5′-tetraethyl-4,4′-diaminodiphenylmethane.

While the term “secondary diamine” is used throughout this document torefer to diamines produced by the processes of this invention in whichboth amino groups are secondary, it is to be understood that theprocesses of this invention produce diamines in which only one of theamino groups is secondary (and the other amino group is primary), albeitusually in small amounts, because the processes of the invention do notnecessarily produce diamine(s) where both amino groups are secondary in100% yield. When the term “aromatic secondary diamine” is used to referto compositions of the invention, it does not generally include aromaticdiamines in which one amino group is secondary and the other amino groupis primary, except as impurities present (usually in small amounts) inthe aromatic secondary diamines.

Compositions of the Invention

A. Aromatic Diimines

An aromatic diimine which is a composition of this invention has atleast two carbon atoms in each imino group (—N═R), and the diimineeither is in the form of one phenyl ring having two imino groups on thering, which imino groups are meta or para relative to each other, and inwhich each position ortho (immediately adjacent) to an imino group bearsa hydrocarbyl group, or is in the form of two phenyl rings connected byan alkylene bridge and having one imino group on each ring, and in whicheach position ortho (immediately adjacent) to an imino group bears ahydrocarbyl group. The hydrocarbyl groups on the phenyl rings may be thesame or different. Examples of suitable hydrocarbyl groups on thearomatic ring include methyl, ethyl, propyl, isopropyl, n-butyl,sec-butyl, t-butyl, pentyl, cyclopentyl, hexyl, methylcyclohexyl,heptyl, octyl, cyclooctyl, nonyl, decyl, dodecyl, phenyl, benzyl, andthe like. When the aromatic diimine is in the form of two phenyl ringsconnected by an alkylene bridge and having one imino group on each ringand the imino group is adjacent (ortho) to the alkylene bridge, thealkylene bridge is considered as a hydrocarbyl group ortho to the iminogroup. Preferred hydrocarbyl groups on the phenyl ring(s) (ortho to animino group) of the aromatic diimines are straight-chain orbranched-chain alkyl groups having from one to about six carbon atoms;particularly preferred hydrocarbyl groups are methyl, ethyl, isopropyl,butyl, and mixtures of two or more of these groups. Here, the preferencefor butyl groups includes n-butyl, sec-butyl, and t-butyl groups. Thealkylene bridge of the two-ringed diimine has from one to about sixcarbon atoms; preferably, the bridge has from one to about three carbonatoms. More preferably, the alkylene bridge has one or two carbon atoms;highly preferred is an alkylene bridge having one carbon atom, i.e., amethylene group.

The hydrocarbylidene groups of the imino groups of the aromatic diiminegenerally have from two to about twenty carbon atoms; thehydrocarbylidene groups may be aliphatic (straight chain, branched, orcyclic) or aromatic. Preferably, the imino hydrocarbylidene groups arestraight chain or branched chain alkylidene groups having from three toabout six carbon atoms. Examples of suitable imino hydrocarbylidenegroups include ethylidene, propylidene, isopropylidene,1-cyclopropylethylidene, n-butylidene, sec-butylidene, cyclobutylidene,2-ethylbutylidene, 3,3-dimethyl-2-butylidene, 3-pentylidene,3-penten-2-ylidene, cyclopentylidene, 2,5-dimethylcyclopentylidene,2-cyclopentenylidene, hexylidene, methylcyclohexylidene, menthylidene,ionylidene, phorylidene, isophorylidene, heptylidene,2,6,-dimethyl-3-heptylidene, cyclooctylidene, 5-nonylidene, decylidene,10-undecenylidene, benzylidene, 2,4-dimethylbenzylidene,2-phenylethylidene, 1-phenylpentylidene, 1-naphthylidene,2-naphthylidene, 1-naphthylethylidene, and the like. Particularlypreferred imino hydrocarbylidene groups are isopropylidene andsec-butylidene.

Preferred aromatic diimines with two imino groups on one phenyl ringhave the imino groups meta relative to each other. In these preferreddiimines, the imino hydrocarbylidene group preferably is a straightchain or branched chain alkylidene group having from three to about sixcarbon atoms. Particularly preferred are aromatic diimines in which thehydrocarbyl group between the two meta imino groups is a methyl group,while the two remaining hydrocarbyl groups are ethyl groups, and thosein which the hydrocarbyl group between the two meta imino groups is anethyl group, while one of the two remaining hydrocarbyl groups is amethyl group and the other is an ethyl group, and mixtures thereof,especially when the imino hydrocarbylidene groups are isopropylidene orsec-butylidene.

Preferred aromatic diimines in which one imino group is on each of twophenyl rings, where the two phenyl rings are connected via an alkylenebridge, have both imino groups para relative to the alkylene bridge. Aparticularly preferred aromatic diimine of this type is a compound whereeach hydrocarbyl group ortho to an imino group is an ethyl group and thealkylene bridge is a methylene group; this is especially preferred whenthe imino hydrocarbylidene groups are isopropylidene or sec-butylidene.

Diimines of the invention having both imino groups on one phenyl ringinclude, but are not limited to,N,N′-diisopropylidene-2,4,6-triethyl-1,3-benzenediamine,N,N′-di-sec-butylidene-2,4,6-triethyl-1,3-benzenediamine,N,N′-di(2-pentylidene)-(2,4,6-triethyl-1,3-benzenediamine),N,N′-diisopropylidene-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-di-sec-butylidene-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-diisopropylidene-(4,6-diethyl-2-methyl-1,3-benzenediamine),N,N′-di-sec-butylidene-(4,6-diethyl-2-methyl-1,3-benzenediamine),N,N′-dicyclobutylidene-(4,6-diethyl-2-methyl-1,3-benzenediamine),N,N′-dicyclopentylidene-(2,4-diisopropyl-6-methyl-1,3-benzenediamine),N,N′-diisopropylidene-(2-methyl-4,6-di-sec-butyl-1,3-benzenediamine),N,N′-di(1-cyclopropylethylidene)-(2-methyl-4,6-di-sec-butyl-1,3-benzenediamine),N,N′-di(3,3-dimethyl-2-butylidene)-(2-ethyl-4-isopropyl-6-methyl-1,3-benzenediamine),N,N′-di(2-butenylidene)-2,4,5,6-tetra-n-propyl-1,3-benzenediamine,N,N′-di-sec-butylidene-2,3,5,6-tetraethyl-1,4-benzenediamine, andN,N′-di(2-phenylethylidene)-2,3,5,6-tetraethyl-1,4-benzenediamine.Particularly preferred aromatic diimines having both imino groups on onephenyl ring areN,N′-diisopropylidene-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-diisopropylidene-(4,6-diethyl-2-methyl-1,3-benzenediamine), andmixtures thereof;N,N′-di-sec-butylidene-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-di-sec-butylidene-(4,6-diethyl-2-methyl-1,3-benzenediamine), andmixtures thereof.

Examples of aromatic diimines of the invention in which one imino groupis on each of two phenyl rings includeN,N′-diisopropylidene-2,2′-methylenebis(6-n-propylbenzeneamine),N,N′-di-sec-butylidene-2,2′-methylenebis(6-n-propylbenzeneamine),N,N′-di-sec-butylidene-2,2′-methylenebis(3,6-di-n-propylbenzeneamine),N,N′-di(1-cyclobutylethylidene)-2,2′-methylenebis(5,6-dihexylbenzeneamine),N,N′-diisopropylidene-3,3′-methylenebis(2,6-di-n-butylbenzeneamine),N,N′-di(2,4-dimethyl-3-pentylidene)-3,3′-methylenebis(2,6-di-n-butylbenzeneamine),N,N′-diisopropylidene-4,4′-methylenebis(2,6-diethylbenzeneamine),N,N′-di-sec-butylidene-4,4′-methylenebis(2,6-diethylbenzeneamine),N,N′-di(benzylidene)-4,4′-methylenebis(2,6-diethylbenzeneamine),N,N′-di(2-heptylidene)-4,4′-methylenebis(2,6-diisopropylbenzeneamine),N,N′-dicyclobutylidene-4,4′-methylenebis(2-isopropyl-6-methylbenzeneamine),N,N′-di(3-methyl-2-cyclohexenylidene)-4,4′-methylenebis(2-methyl-6-tert-butylbenzeneamine),N,N′-di-sec-butylidene-4,4′-(1,2-ethanediyl)bis(2,6-diethylbenzeneamine),N,N′-di(1-cyclopentylethylidene)-4,4′-(1,2-ethanediyl)bis(2,6-diethylbenzeneamine),N,N′-di(1-phenyl-2-butylidene)-4,4′-(1,2-ethanediyl)bis(2,6-diisopropylbenzeneamine),N,N′-di(2-phenylethylidene)-2,2′-methylenebis(3,4,6-tripentylbenzeneamine),N,N′-di(4-heptylidene)-3,3′-methylenebis(2,5,6-trihexylbenzeneamine),N,N′-dicyclohexylidene-4,4′-methylenebis(2,3,6-trimethylbenzeneamine),N,N′-di(1-cyclobutylethylidene)-4,4′-methylenebis(2,3,4,6-tetramethylbenzeneamine),and the like. Particularly preferred aromatic diimines in which oneimino group is on each of two phenyl rings areN,N′-diisopropylidene-4,4′-methylenebis(2,6-diethylbenzeneamine) andN,N′-di-sec-butylidene-4,4′-methylenebis(2,6-diethylbenzeneamine).

B. Aromatic Secondary Diamines

An aromatic secondary diamine which is a composition of the invention isa secondary diamine in which each amino group (—NHR) has at least twocarbon atoms, and which diamine either is in the form of one phenyl ringhaving two amino groups on the ring, which amino groups are meta or pararelative to each other, and in which each position ortho (immediatelyadjacent) to an amino group bears a hydrocarbyl group, or is in the formof two phenyl rings connected by an alkylene bridge and having one aminogroup on each ring, and in which each position ortho (immediatelyadjacent) to an amino group bears a hydrocarbyl group. The hydrocarbylgroups ortho to the amino groups on the phenyl rings may be the same ordifferent. Examples of suitable hydrocarbyl groups on the aromatic ringinclude methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl,pentyl, cyclopentyl, hexyl, methylcyclohexyl, heptyl, octyl, cyclooctyl,nonyl, decyl, dodecyl, phenyl, benzyl, and the like. When the aromaticdiamine is in the form of two phenyl rings connected by an alkylenebridge and having one amino group on each ring and the amino group isadjacent (ortho) to the alkylene bridge, the alkylene bridge isconsidered as a hydrocarbyl group ortho to the amino group. Preferredhydrocarbyl groups on the phenyl rings (ortho to an amino group) of thearomatic secondary diamines are straight chain or branched chain alkylgroups having from one to about six carbon atoms; particularly preferredhydrocarbyl groups are methyl, ethyl, isopropyl, butyl, and mixtures oftwo or more of these groups. Here, the preference for butyl groupsincludes n-butyl, sec-butyl, and t-butyl groups. The alkylene bridge ofthe two-ring diamine has from one to about six carbon atoms; preferably,the alkylene bridge has from one to about three carbon atoms. Morepreferably, the alkylene bridge has one or two carbon atoms; highlypreferred is an alkylene bridge having one carbon atom, i.e., amethylene group. Particularly preferred amino hydrocarbyl groups areisopropyl and sec-butyl groups.

Throughout this document, the term “amino hydrocarbyl group” refers tothe hydrocarbyl group bound to a nitrogen atom of the aromatic secondarydiamine which hydrocarbyl group is not the phenyl ring to which thenitrogen atom is bound in order to form the aromatic diamine.

The amino hydrocarbyl groups of the aromatic secondary diamine generallyhave from two to about twenty carbon atoms; the amino hydrocarbyl groupmay be aliphatic (straight chain, branched, or cyclic) or aromatic.Preferably, the amino hydrocarbyl groups are straight chain or branchedchain alkyl groups having from three to about six carbon atoms. Examplesof suitable amino hydrocarbyl groups include ethyl, propyl, isopropyl,1-cyclopropylethyl, n-butyl, sec-butyl, cyclobutyl, 2-ethylbutyl,3,3-dimethyl-2-butyl, 3-pentyl, 3-penten-2-yl, cyclopentyl,2,5-dimethylcyclopentyl, 2-cyclopentenyl, hexyl, methylcyclohexyl,menthyl, ionyl, phoryl, isophoryl, heptyl, 2,6,-dimethyl-3-heptyl,cyclooctyl, 5-nonyl, decyl, 10-undecenyl, dodecyl, benzyl,2,4-dimethylbenzyl, 2-phenylethyl, 1-phenylpentyl, 1-naphthyl,2-naphthyl, 1-naphthylethyl, and the like. Particularly preferred aminohydrocarbyl groups are isopropyl and sec-butyl.

Preferred aromatic secondary diamines with two amino groups on onephenyl ring have the amino groups meta relative to each other. In suchpreferred aromatic secondary diamines, the amino hydrocarbyl grouppreferably is a straight chain or branched chain alkyl group having fromthree to about six carbon atoms. Particularly preferred are aromaticsecondary diamines in which the hydrocarbyl group between the two metaamino groups is a methyl group, while the two remaining hydrocarbylgroups are ethyl groups, and those in which the hydrocarbyl groupbetween the two meta amino groups is an ethyl group, while one of thetwo remaining hydrocarbyl groups is a methyl group and the other is anethyl group, and mixtures thereof, especially when the amino hydrocarbylgroups are isopropyl or sec-butyl groups.

Preferred aromatic secondary diamines in which one amino group is oneach of two phenyl rings, where the two phenyl rings are connected viaan alkylene bridge, have both amino groups para relative to the alkylenebridge. A particularly preferred aromatic secondary diamine of this typeis a compound where each hydrocarbyl group ortho to an amino group is anethyl group and the alkylene bridge is a methylene group; this isespecially preferred when the amino hydrocarbyl groups are isopropyl orsec-butyl groups.

Aromatic secondary diamines of this invention having both amino groupson one phenyl ring include, but are not limited to,N,N′-diisopropyl-2,4,6-triethyl-1,3-benzenediamine,N,N′-di-sec-butyl-2,4,6-triethyl-1,3-benzenediamine,N,N′-di-2-pentyl-2,4,6-triethyl-1,3-benzenediamine,N,N′-diisopropyl-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-di-sec-butyl-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-diisopropyl-(4,6-diethyl-2-methyl-1,3-benzenediamine),N,N′-di-sec-butyl-(4,6-diethyl-2-methyl-1,3-benzenediamine),N,N′-di(2-naphthyl)-(4,6-diethyl-2-methyl-1,3-benzenediamine),N,N′-di(2-cyclopentenyl)-(2,4-diisopropyl-6-methyl-1,3-benzenediamine),N,N′-diisopropyl-(2-methyl-4,6-di-sec-butyl-1,3-benzenediamine),N,N′-di-sec-butyl-(2-methyl-4,6-di-sec-butyl-1,3-benzenediamine),N,N′-di(1-cyclopropylethyl)-(2-methyl-4,6-di-sec-butyl-1,3-benzenediamine),N,N′-di(3,3-dimethyl-2-butyl)-(2-ethyl-4-isopropyl-6-methyl-1,3-benzenediamine),N,N′-diisopropyl-2,4,5,6-tetra-n-propyl-1,3-benzenediamine,N,N′-di(3-penten-2-yl)-2,4,5,6-tetra-n-propyl-1,3-benzenediamine, andN,N′-di(4-hexyl)-2,3,5,6-tetraethyl-1,4-benzenediamine. Particularlypreferred aromatic diamines having both amino groups on one phenyl ringare N,N′-diisopropyl-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-diisopropyl-(4,6-diethyl-2-methyl-1,3-benzenediamine), and mixturesthereof; N,N′-di-sec-butyl-(2,4-diethyl-6-methyl-1,3-benzenediamine),N,N′-di-sec-butyl-(4,6-diethyl-2-methyl-1,3-benzenediamine), andmixtures thereof.

Examples of aromatic secondary diamines of the invention in which oneamino group is on each of two phenyl rings includeN,N′-diisopropyl-2,2′-methylenebis(6-n-propylbenzeneamine),N,N′-di-sec-butyl-2,2′-methylenebis(3,6-di-n-propylbenzeneamine),N,N′-di(2,4-dimethylbenzyl)-2,2′-methylenebis(5,6-dihexylbenzeneamine),N,N′-diisopropyl-3,3′-methylenebis(2,6-di-n-butylbenzeneamine),N,N′-di(2,4-dimethyl-3-pentyl)-3,3′-methylenebis(2,6-di-n-butylbenzeneamine),N,N′-diisopropyl-4,4′-methylenebis(2,6-diethylbenzeneamine),N,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine),N,N′-di(2-hexyl)-4,4′-methylenebis(2,6-diethylbenzeneamine),N,N′-di(1-naphthylethyl)-4,4′-methylenebis(2,6-diisopropylbenzeneamine),N,N′-dicyclobutyl-4,4′-methylenebis(2-isopropyl-6-methylbenzeneamine),N,N′-di(1-penten-3-yl)-4,4′-methylenebis(2-methyl-6-tert-butylbenzeneamine),N,N′-di-sec-butyl-4,4′-(1,2-ethanediyl)bis(2,6-diethylbenzeneamine),N,N′-di(1-cyclopentylethyl)-4,4′-(1,2-ethanediyl)bis(2,6-diethylbenzeneamine),N,N′-di(2-ethylbutyl)-4,4′-(1,2-ethanediyl)bis(2,6-diisopropylbenzeneamine),N,N′-di(10-undecenyl)-2,2′-methylenebis(3,4,6-tripentylbenzeneamine),N,N′-di(4-heptyl)-3,3′-methylenebis(2,5,6-trihexylbenzeneamine),N,N′-dimenthyl-4,4′-methylenebis(2,3,6-trimethylbenzeneamine),N,N′-dibenzyl-4,4′-methylenebis(2,3,4,6-tetramethylbenzeneamine), andthe like. Particularly preferred aromatic diamines in which one aminogroup is on each of two phenyl rings areN,N′-diisopropyl-4,4′-methylenebis(2,6-diethylbenzeneamine) andN,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine).

Components of the Processes of the Invention

A. Ketones and Aldehydes

In the processes of the invention, hydrocarbyl ketones and hydrocarbylaldehydes are used. The hydrocarbyl portion of the ketone or aldehydemay be aliphatic (cyclic, branched, or straight chain), unsaturated,aromatic, or alkylaromatic. The hydrocarbyl portion is preferablyaliphatic, alkylaromatic, or aromatic. More preferably, the hydrocarbylportion of the aldehyde or ketone is an aliphatic straight chain or abranched aliphatic group; especially preferred is an aliphatic straightchain. Regarding ketones, this preference for an aliphatic straightchain refers to the hydrocarbyl portions on both sides of the carbonylgroup. Preferably, the ketones and aldehydes used in the practice ofthis invention have from three to about twenty carbon atoms. Morepreferred are ketones and aldehydes having from three to about fifteencarbon atoms. Especially preferred ketones and aldehydes have ahydrocarbyl portion which is an aliphatic straight chain or a branchedaliphatic group, and have from three to about fifteen carbon atoms.

The mole ratio of the ketone or aldehyde to the primary diamine isnormally at least about one mole of ketone or aldehyde per mole of aminogroup, i.e., at least about two moles of ketone or aldehyde per mole ofdiamine. Preferably, an excess of the ketone or aldehyde is used, morepreferably at least about a 10% molar excess of ketone or aldehyderelative to the primary diamine is used. Large excesses of ketone oraldehyde are acceptable in the practice of the invention; the ketone oraldehyde can be, and preferably is, present in enough quantity to alsoact as a solvent. In fact, a large excess of ketone or aldehyde isconsidered beneficial because, as is well known in the art, theformation of a diimine behaves as an equilibrium, and excess ketone oraldehyde helps shift the equilibrium to favor diimine formation.

Suitable ketones include acetone (2-propanone), methyl ethyl ketone(2-butanone), 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone,2-heptanone, 4-heptanone, 3-octanone, 4-octanone, 3-nonanone,5-nonanone, 2-undecanone, 6-undecanone, di-n-hexyl ketone,8-pentadecanone, 9-heptadecanone, 10-nonadecanone, cyclobutanone,cyclopentanone, cyclohexanone, cyclopropyl methyl ketone(1-(cyclopropyl)ethanone), cyclobutyl methyl ketone, cyclopentyl methylketone, cyclohexyl methyl ketone, 3-methyl-2-pentanone,4-methyl-2-pentanone (methyl isobutyl ketone), 2-methyl-cyclopentanone,3-methyl-cyclopentanone, 5-methyl-2-hexanone, 4-methyl-3-heptanone,3,3-dimethyl-2-butanone (methyl tert-butyl ketone),2,4-dimethyl-3-pentanone, 2,6-dimethyl-3-heptanone,3,5-dimethyl-4-heptanone, 2-methylcyclohexanone,2,5-dimethylcyclopentanone, menthone, ethyl vinyl ketone(1-penten-3-one), 3-penten-2-one, 2-cyclopentenone, α-ionone, β-ionone,phorone(2,6-dimethyl-2,5-heptadien-4-one), isophorone,1,3-diphenylacetone, phenylacetone(phenyl-2-propanone),1-phenyl-2-butanone, acetophenone, isobutyrophenone,valerophenone(1-phenyl-1-pentanone), hexanophenone, 1-acetonaphthone,and the like. Preferred ketones include acetone, methyl ethyl ketone,methyl isobutyl ketone, 3,3-dimethyl-2-butanone, cyclohexanone,4-heptanone, and 5-nonanone. Acetone, methyl ethyl ketone 4-heptanone,3,3-dimethyl-2-butanone, and 4-methyl-2-pentanone are particularlypreferred ketones in the practice of this invention.

Aldehydes that can be used in the practice of this invention includeacetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde (pentanal),isovaleraldehyde, hexanal, cyclohexanecarboxaldehyde, heptaldehyde,octyl aldehyde, nonyl aldehyde, decyl aldehyde, undecyl aldehyde,dodecyl aldehyde, 2-ethylbutyraldehyde, crotonaldehyde, undecylenicaldehyde (10-undecenal), cinnamaldehyde, phenylacetaldehyde,benzaldehyde, 2,4-dimethylbenzaldehyde, tolualdehyde, mesitaldehyde,1-naphthaldehyde, and the like. Preferred aldehydes include acetaldehydeand propionaldehyde.

While the use of either one ketone or one aldehyde is preferred,mixtures may be employed. Such mixtures can include two or more ketones,two or more aldehydes, or at least one ketone and at least one aldehyde.The use of a mixture of ketones and/or aldehydes may result in a mixtureof products.

Usually, the ketone and/or aldehyde is in liquid form when it is used inthe processes of the invention. For some ketones and aldehydes, elevatedtemperatures and/or increased pressure will liquefy the ketone oraldehyde. If such conditions are not used, a solvent may be used toprovide the ketone or aldehyde in liquid form.

B. Acid Ion Exchange Resins

It is known in the art that strong acids such as H₂SO₄ often causealiphatic ketones to dimerize and/or polymerize. Thus, a feature of thisinvention is the use of an acid ion exchange resin as the acid catalystfor the formation of the diimines of the invention. Acid ion exchangeresins are generally polymers containing protic acid functional groups,where the protic acid functional group, at least in theory, can donate aproton. Using an acid ion exchange resin provides the needed acid forthe formation of the diimines. Since acid ion exchange resins areusually solids, dimerization and polymerization of the ketone isminimized. In addition, acid ion exchange resins do not add significantamounts of water to the system, another advantage, because water,especially in large amounts, can shift the equilibrium toward the ketoneand primary diamine. Additionally, acid ion exchange resins can be driedto remove water present in the resin, and acid ion exchange resins canbe recycled. A particularly preferred acid ion exchange resin issulfonated divinylbenzene/styrene copolymer, in H ion form, sold asAmberlyst-15 (Rohm and Haas Company), in which the protic acidfunctional group is —SO₃H. In the processes of the invention where it isused, the acid ion exchange resin is typically present in amounts ofabout 1 wt % to about 10 wt % relative to the primary diamine.Preferably, about 3 wt % to about 7 wt % acid ion exchange resin is usedrelative to the primary diamine.

C. Hydrogenation Agents

Various hydrogenation agents can be used in the processes of theinvention. Which hydrogenation agents are suitable depends on theprimary diamine used in the process. Types of hydrogenation agents thatcan be used include hydride transfer agents such as sodiumcyanoborohydride, sodium borohydride, sodium aluminum hydride, lithiumaluminum hydride, and the like; “dissolving metal” reagents such as Alwith alcohol, Al/Hg, Al/Pd with HCl, Na with alcohol, Na/Hg, Mg withalcohol, Fe with HCl, Zn with HCl, Zn/Cu with HCl, Zn/Hg with HCl, Zn/Pdwith HCl, Zn/Cu/Pd with HCl, and the like; borane reductants includingBH₃-pyridine and BH₃-dimethylamine; and hydrogen with a hydrogenationcatalyst, where the hydrogenation catalyst can be sulfided platinum oncarbon, sulfided palladium on carbon, or a mixture of both of these. Allof these hydrogenation agents are normally suitable for processes of theinvention in which the primary diamine is an aliphatic diamine or anaromatic diamine in which at least one position ortho to each aminogroup has a hydrogen atom as a substituent (see below). A preferred typeof hydrogenation agent is hydrogen with a hydrogenation catalyst; anespecially preferred hydrogenation catalyst is sulfided platinum oncarbon.

Some of the just-described hydrogenation agents do not seem to be aseffective when the primary diamine is an aromatic primary diamine inwhich each position ortho to an amino group bears a hydrocarbyl group(see below). In particular, hydride transfer agents react very slowlywith aromatic primary diamines in which each position ortho to an aminogroup bears a hydrocarbyl group, sometimes forming gels; in addition, todate, palladium on carbon and platinum on carbon (unsulfided, or withouta strong acid present) have not yielded observable products when usedwith an aromatic primary diamine in which each position ortho to anamino group bears a hydrocarbyl group. Palladium on carbon and platinumon carbon can be effective hydrogenation catalysts in the presence ofhydrogen sulfide or a strong acid such as sulfuric acid, hydrochloricacid, phosphoric acid, and the like, for processes using aromaticprimary diamines in which each position ortho to an amino group bears ahydrocarbyl group. Thus, for aromatic primary diamines in which eachposition ortho to an amino group bears a hydrocarbyl group, thehydrogenation agent is generally either a dissolving metal reagent orhydrogen with a hydrogenation catalyst, where the hydrogenation catalystis sulfided platinum on carbon, sulfided palladium on carbon, or amixture thereof, or is selected from palladium on carbon, platinum oncarbon, and a mixture of both of these, when used with hydrogen sulfideor at least one strong acid. In the practice of this invention, sulfidedplatinum on carbon, Pt(S)/C, has been found to be a particularlyeffective hydrogenation catalyst for aromatic primary diamines in whicheach position ortho to an amino group bears a hydrocarbyl group; thushydrogen with sulfided platinum on carbon is an especially preferredhydrogenation agent for processes employing aromatic primary diamines inwhich each position ortho to an amino group bears a hydrocarbyl group.Preferred amounts of sulfided platinum on carbon are in the range ofabout 0.5 wt % to about 10 wt % relative to the primary diamine. Morepreferably, in the range of about 0.75 wt % to about 6 wt % sulfidedplatinum on carbon is used relative to the primary diamine. A weightratio of primary diamine to catalyst in the range of about 20:1 to about1:20 is feasible, and a weight ratio of primary diamine to hydrogenationcatalyst in the range of about 10:1 to about 1:10 is preferred; morepreferred is a weight ratio of primary diamine to hydrogenation catalystin the range of about 1:1 to about 1:5.

When choosing a hydrogenation agent, especially the “dissolving metal”reagents which are used in conjunction with acid, and hydrogen with ahydrogenation catalyst where acid will be present, it should beremembered that, as mentioned above, strong acids can cause dimerizationand/or polymerization of some ketones.

D. Aromatic Primary Diamines

One type of aromatic primary diamine used in the processes of theinvention has at least one position ortho to each amino group which hasa hydrogen atom as a substituent, and the aromatic primary diamine iseither in the form of one phenyl ring having two amino groups on thering, or in the form of two phenyl rings connected by an alkylene bridgeand having one amino group on each ring. The phenyl rings may have, butneed not have, one or more hydrocarbyl groups on the phenyl ring(s).Hydrocarbyl groups, when present on the phenyl rings, may be the same ordifferent. When both amino groups are on one phenyl ring, the aminogroups may be in any position relative to each other on the ring;preferably, the amino groups are meta or para relative to each other.When the amino groups are on two phenyl rings connected by an alkylenebridge, they may be in any position on the rings; preferably, each aminogroup is meta or para relative to the alkylene bridge. The alkylenebridge of the two-ring diamine has from one to about six carbon atoms;preferably, the alkylene bridge has from one to about three carbonatoms. More preferably, the alkylene bridge has one or two carbon atoms;highly preferred is an alkylene bridge having one carbon atom. Thehydrocarbyl groups, when present on the phenyl ring(s), are as describedabove for the aromatic diimines. When one or more hydrocarbyl groups arepresent on the phenyl ring(s), the hydrocarbyl groups can have from oneto about twenty carbon atoms; preferably, the hydrocarbyl groups havefrom one to about six carbon atoms.

Suitable aromatic primary diamines having both amino groups on onephenyl ring include, but are not limited to, 1,2-benzenediamine,1,3-benzenediamine, 1,4-benzenediamine, 4-ethyl-1,2-benzenediamine,2-isopropyl-1,3-benzenediamine, 4-tert-butyl-1,3-benzenediamine,2-pentyl-1,4-benzenediamine, 4,5-dihexyl-1,2-benzenediamine,4-methyl-5-heptyl-1,3-benzenediamine,4,6-di-n-propyl-1,3-benzenediamine, 2,5-dioctyl-1,4-benzenediamine,2,3-diethyl-1,4-benzenediamine, and 4,5,6-trihexyl-1,3-benzenediamine.Preferred aromatic primary diamines having both amino groups on onephenyl ring and at least one position ortho to each amino group has ahydrogen atom as a substituent include 1,3-benzenediamine and1,4-benzenediamine.

Examples of suitable aromatic primary diamines in which one amino groupis on each of two phenyl rings include 2,2′-methylenebis(benzeneamine),2,3′-methylenebis-(benzeneamine), 2,4′-methylenebis(benzeneamine),3,3′-methylenebis(benzeneamine), 3,4′-methylenebis(benzeneamine),4,4′-methylenebis(benzeneamine),4,4′-(1,2-ethanediyl)bis-(benzeneamine),3,4′-(1,3-propanediyl)bis(benzeneamine),2,2′-methylenebis(5-tert-butyl-benzeneamine),3,3′-methylenebis(2-methylbenzeneamine),3,3′-methylenebis(5-pentylbenzeneamine),3,3′-methylenebis(6-isopropylbenzeneamine),4,4′-methylenebis(2-methylbenzeneamine),4,4′-methylenebis(3-sec-butylbenzeneamine),4,4′-(1,2-ethanediyl)bis(2-methylbenzeneamine),3,3′-methylenebis(2,4-dipentylbenzeneamine),3,3′-methylenebis(5,6-diisopropylbenzeneamine),4,4′-methylenebis(2,3-di-sec-butylbenzeneamine),4,4′-methylenebis(3,5-di-tert-butylbenzeneamine), and the like.Preferred aromatic primary diamines in which one amino group is on eachof two phenyl rings and at least one position ortho to each amino grouphas a hydrogen atom as a substituent include4,4′-methylenebis(benzeneamine) and4,4′-methylenebis(2-methylbenzeneamine).

E. Preferred Aromatic Primary Diamines

Another type of aromatic primary diamine for use in the processes of theinvention, which is a preferred type of aromatic primary diamine, is anaromatic primary diamine in which each position ortho (immediatelyadjacent) to an amino group bears a hydrocarbyl group, and whicharomatic primary diamine either is in the form of one phenyl ring havingtwo amino groups on the ring, which amino groups are meta or pararelative to each other, or is in the form of two phenyl rings connectedby an alkylene bridge and having one amino group on each ring. Thehydrocarbyl groups on the phenyl rings (adjacent to the amino groups)generally have up to about twenty carbon atoms, and the hydrocarbylgroups may be the same or different. The alkylene bridge of the two-ringprimary diamine has from one to about six carbon atoms; preferably, thebridge has from one to about three carbon atoms. More preferably, thealkylene bridge has one or two carbon atoms; especially preferred as thealkylene bridge is a methylene group. Particularly preferred hydrocarbylgroups on the phenyl ring(s) are methyl, ethyl, isopropyl, butyl, andmixtures of two or more of these groups. Here, butyl groups includen-butyl, sec-butyl, and t-butyl groups.

More preferred aromatic primary diamines with two amino groups on onephenyl ring have the amino groups meta relative to each other. In thesemore preferred aromatic primary diamines, the amino hydrocarbyl grouppreferably is a straight-chain or branched-chain alkyl group having fromone to about six carbon atoms. Highly preferred hydrocarbyl groups aremethyl, ethyl, isopropyl, butyl, and mixtures thereof, where thepreference for butyl groups includes n-butyl, sec-butyl, and t-butylgroups. Particularly preferred are aromatic primary diamines in whichthe hydrocarbyl group between the two meta amino groups is a methylgroup, while the two remaining hydrocarbyl groups, are ethyl groups andthose in which the hydrocarbyl group between the two meta amino groupsis an ethyl group, while one of the two remaining hydrocarbyl groups isa methyl group and the other is an ethyl group, and mixtures thereof.More preferred aromatic primary diamines are also those in which oneamino group is on each of two phenyl rings, where the two phenyl ringsare connected via an alkylene bridge, and have both amino groups pararelative to the alkylene bridge. An especially preferred aromaticprimary diamine of this type is a compound where each hydrocarbyl grouportho to an amino group is an ethyl group and the alkylene bridge is amethylene group. Examples of more preferred aromatic primary diaminesinclude 3,6-di-n-butyl-1,2-benzenediamine,2,4,6-triethyl-1,3-benzenediamine,2,4-diethyl-6-methyl-1,3-benzenediamine,4,6-diethyl-2-methyl-1,3-benzenediamine,2,4-diisopropyl-6-methyl-1,3-benzenediamine,2-methyl-4,6-di-sec-butyl-1,3-benzenediamine,2-ethyl-4-isopropyl-6-methyl-1,3-benzenediamine,2,3,5-tri-n-propyl-1,4-benzenediamine,2,3-diethyl-5-sec-butyl-1,4-benzenediamine,3,4-dimethyl-5,6-diheptyl-1,2-benzenediamine,2,4,5,6-tetra-n-propyl-1,3-benzenediamine,2,3,5,6-tetraethyl-1,4-benzenediamine,2,2′-methylenebis(6-n-propylbenzeneamine),2,2′-methylenebis(3,6-di-n-propylbenzeneamine),3,3′-methylenebis(2,6-di-n-butylbenzeneamine),4,4′-methylenebis(2,6-diethylbenzeneamine),4,4′-methylenebis(2,6-diisopropylbenzeneamine),4,4′-methylenebis(2-isopropyl-6-methylbenzeneamine),4,4′-(1,2-ethanediyl)bis(2,6-diethylbenzeneamine),4,4′-(1,2-ethanediyl)bis(2,6-diisopropylbenzeneamine),2,2′-methylenebis(3,4,6-tripentylbenzeneamine),3,3′-methylenebis(2,5,6-trihexylbenzeneamine),4,4′-methylenebis(2,3,6-trimethylbenzeneamine),4,4′-methylenebis(2,3,4,6-tetramethylbenzeneamine), and the like. Ofthese more preferred types of aromatic primary diamines, particularlypreferred are 4,4′-methylenebis(2,6-diethylbenzeneamine),4,4′-methylenebis(2,6-diisopropylbenzeneamine), and a mixture of2,4-diethyl-6-methyl-1,3-benzenediamine and4,6-diethyl-2-methyl-1,3-benzenediamine (DETDA). Throughout thisdocument, when the term “more preferred aromatic primary diamine” isused, it is meant to refer to aromatic primary diamines of the typedescribed in this paragraph. The use of more preferred aromatic primarydiamines in the processes of the present invention produce compositionsof the invention.

F. Aliphatic Primary Diamines

The aliphatic primary diamines used in the processes of this inventionare hydrocarbyl primary diamines where the hydrocarbyl portion of thediamine is aliphatic. The hydrocarbyl portion of the aliphatic diaminecan be cyclic, branched, or straight chain. Preferably, the aliphaticprimary diamine has about two to about twenty carbon atoms; morepreferably, the aliphatic primary diamine has about four to about tencarbon atoms. Particularly preferred aliphatic diamines have cyclic orstraight chain hydrocarbyl portions and have about four to about tencarbon atoms. Suitable aliphatic primary diamines include, but are notlimited to, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane,1,4-diaminobutane, 1,5-diaminopentane, 1,5-diamino-2-methylpentane,1,6-diaminohexane, 2,5-dimethyl-2,5-hexanediamine,1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane,2,4-diethyl-6-methyl-1,3-cyclohexanediamine,4,6-diethyl-2-methyl-1,3-cyclohexanediamine,1,3-cyclohexanebis(methylamine), 1,4-cyclohexanebis(methylamine),isophorone diamine, bis(p-aminocyclohexyl)methane,bis(3-methyl-4-aminocyclohexyl)methane, 1,8-diamino-p-menthane,1,7-diaminoheptane, 1,8-diaminooctane, 1,10-diaminodecane,1,12-diaminododecane, and3(4),8(9)-bis-(aminomethyl)-tricyclo[5.2.1.0(2,6)]decane (TCD diamine;also called octahydro-4,7-methanoinden-1(2),5(6)-dimethanamine oroctahydro-4,7-methano-1H-indenedimethyl-amine). Preferred aliphaticprimary diamines include isophorone diamine, 1,6-diaminohexane,1,8-diaminooctane, and TCD diamine. Particularly preferred combinationsin the processes of this invention are the use of isophorone diaminewith 5-nonanone, the use of isophorone diamine with cyclohexanone, theuse of isophorone diamine with methyl isobutyl ketone, the use ofisophorone diamine with 4-heptanone, the use of isophorone diamine with3,3-dimethyl-2-butanone, the use of 1,6-diaminohexane with3,3-dimethyl-2-butanone, and the use of TCD diamine with3,3-dimethyl-2-butanone.

G. Solvents

It is often preferred to use a large enough excess of ketone or aldehydesuch that the ketone or aldehyde serves as the solvent in the processesof the invention; however, one or more solvents can be present duringthe processes of the invention. For processes where an acid ion exchangeresin is present, the inclusion of solvent is generally consideredunnecessary. Solvents that can be used in processes where an acid ionexchange resin is present include, but are not limited to, liquidaromatic hydrocarbons, liquid aliphatic hydrocarbons, liquid halogenatedaliphatic hydrocarbons, ethers, esters, alcohols, and mixtures of two ormore solvents. For processes in which a hydrogenation agent is present,the presence of a solvent is not required, but inclusion of a solvent isrecommended and preferred. While the processes will make the desiredproduct in the absence of solvent, the resultant mixture is frequently avery thick, viscous mixture which is often difficult to process further.The important consideration in selecting a solvent is that it notinterfere with the functioning of the chosen hydrogenation agent; forexample, the solvent chosen should not poison the hydrogenationcatalyst. Solvent types that can be used when a hydrogenation agent ispresent include, but are not limited to, liquid aromatic hydrocarbons,liquid aliphatic hydrocarbons, liquid halogenated aliphatichydrocarbons, ethers, esters, alcohols, and a mixture of two or moresolvents. When both an acid ion exchange resin and a hydrogenation agentare present in the same process, solvents that are compatible with bothare selected.

Suitable liquid hydrocarbons include benzene, toluene, xylenes,mesitylene, cumene, cymene, pentane, hexane, isohexane, cyclohexane,methylcyclohexane, heptane, octane, cyclooctane, nonane, and the like.Examples of liquid halogenated aliphatic hydrocarbons that can be usedinclude dichloromethane, trichloromethane, 1,2-dichloroethane,1-bromo-2-chloroethane,(chloromethyl)cyclopropane, 1-bromobutane,cyclobutyl chloride, neopentyl chloride, 1-bromo-5-chloropentane,cyclopentyl bromide, 1,6-dibromohexane, trans-1,2-dichlorocyclohexane,1-chloroheptane, 1,8-dichlorooctane, and the like. Ethers that aresuitable for use in this invention include diethyl ether, di-n-propylether, diisopropyl ether, di-n-butyl ether, butyl ethyl ether,cyclohexylmethyl ether, tetrahydrofuran, 1,3-dioxane, 1,3-dioxolane,glyme (the dimethyl ether of ethylene glycol), 2-methoxyethyl ether(diglyme), and the like. Examples of esters that can be used includeethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate,tert-butyl acetate, n-amyl acetate, isoamyl acetate, hexyl acetate,methyl propionate, ethyl propionate, ethyl butyrate, and the like.Alcohols that can be used in the practice of the invention includemethanol, ethanol, 1-propanol, 2-propanol, 1-butanol,2-methyl-1-propanol, 1-methyl-1-propanol, cyclopropylmethanol,cyclobutanol, cyclopentanol, cis-2-methylcyclohexanol, and the like.Preferred solvents when a hydrogenation agent is present includedichloromethane, ethyl acetate, and toluene.

H. Water Removal Agents

As described below, the presence of large amounts of water in theprocesses of the invention is usually not desirable. Without wishing tobe bound by theory, it is believed that the presence of large amounts ofwater causes hydrolysis of the diimines. However, it has now been foundthat the presence of water may be less detrimental than previouslybelieved in the processes of the invention, or at least in the processesof the invention which employ hydrogen and a hydrogenation catalyst,particularly when two phases can be formed in the reaction productmixture (e.g., an aqueous phase and an organic phase).

One method for minimizing the amount of water in the reaction mixture isto use a water removal agent. A water removal agent may be included inthe reaction mixture to remove water as it is produced in the process.The only requirement is that the water removal agent not adverselyaffect the reaction or its products. Suitable water removal agentsinclude molecular sieves, silica gel, calcium chloride, and the like.Molecular sieves are a preferred water removal agent in the practice ofthis invention.

An alternative to the use of a water removal agent is the inclusion of asolvent or enough excess ketone or aldehyde to act as the solvent toeffectively dilute the water, and is a recommended and preferred way ofoperating. When a solvent is used, a solvent that is able to azeotropewith water and thereby remove water as it is produced during a processis a preferred way of operating. Particularly preferred solvents thatremove water are hexanes and toluene. Another preferred way of operatingwhen using a solvent is to use a solvent which takes water into a phaseseparate from that in which the reaction is occurring; preferredsolvents for this way of operating include toluene and dichloromethane.Both inclusion of a solvent or enough excess ketone or aldehyde to actas the solvent and the use of a water removal agent may be employed tominimize the amount of water. An especially preferred way of operatingis to employ enough excess ketone or aldehyde to dilute the water.

Processes of the Invention

Normally, when an aromatic primary diamine is used, the hydrocarbylgroups on the aromatic ring and the placement of the amino groups on thering(s) of the aromatic diimine and/or the aromatic secondary diamineformed in the processes of the invention correspond to those hydrocarbylgroups and the placement of the amino groups in aromatic primary diaminebeing used in the process.

Large amounts of water are usually undesired during the processes of theinvention because such water shifts the equilibrium toward the ketone oraldehyde and the primary diamine, since water is produced during theformation of a diimine. Without wishing to be bound by theory, in theprocesses of the invention in which a secondary diamine is prepared froma primary diamine, it is believed that a diimine is formed as anintermediate; therefore, large amounts of water are generally notdesired in such processes. However, the presence of water, especially insmall amounts, during the processes of the invention is not detrimental.Thus, the use of a solvent that is able to azeotrope with water andthereby remove water as it is produced during a process is a preferredway of operating. Particularly preferred solvents that remove water arehexanes and toluene. Another preferred way of operating is to use asolvent which takes water into a phase separate from that in which thereaction is occurring; preferred solvents for this way of operatinginclude toluene and dichloromethane. The presence of a solvent in ahydrogenation is not required, but inclusion of a solvent or enoughexcess ketone or aldehyde to act as the solvent is recommended andpreferred, because of the viscous nature of the product mixture, asdescribed above under the discussion of solvents.

In the processes of this invention, the presence of oxygen is generallynot detrimental. The presence of an inert atmosphere comprised of one ormore inert gases, such as, for example, nitrogen, helium, or argon isoften preferred, especially during hydrogenations which do not involvehydrogen gas. Operation under a blanket of hydrogen is preferred whenthe hydrogenation agent is hydrogen and a hydrogenation catalyst.

A. Process for Forming a Diimine Using an Acid Ion Exchange Resin

Diimines, including the aromatic diimines that are compositions of thepresent invention, can be prepared by mixing together a ketone or analdehyde and a primary diamine in the presence of an acid ion exchangeresin. The order of addition of the ketone, acid ion exchange resin,primary diamine, and optional solvent to the reaction zone for thepreparation of the diimine is not considered important. Preferably, theprimary diamine and the ketone are mixed together prior to the additionof the acid ion exchange resin and, if used, solvent. Generally, duringthe preparation of a diimine from a primary diamine in the presence ofan acid ion exchange resin, the temperature is kept in the range ofabout 35° C. to about reflux temperature; preferably, the temperature issuch that the mixture is at about reflux temperature. Reaction times onthe laboratory scale are on the order of about four hours to about sixtyhours.

At least a portion of a diimine formed in this process can behydrogenated to form a secondary diamine. The diimine can be isolatedfrom the reaction medium in which it was formed prior to thehydrogenation; however, the hydrogenation can be performed successfullywithout isolating the diimine from the reaction medium in which it wasformed.

A secondary diamine can be prepared by mixing together a suitablehydrogenation agent and the diimine. For the hydrogenation of thediimine, it is not necessary to exclude water. Temperatures for thehydrogenation of a diimine to form a secondary diamine are normally inthe range of about 20° C. to about 130° C.; preferably, temperatures arein the range of about 20° C. to about 60° C. On the laboratory scale,reaction times are typically about four hours to about twenty hours.When hydrogen and a hydrogenation catalyst are used, the hydrogen gaspressure is preferably in the range of about 14 pounds per square inch(psi) to about 300 psi (9.65×10⁴ to 2.07×10⁶ Pa); more preferably, thepressure is in the range of about 50 psi to about 150 psi (3.45×10⁵ to1.03×10⁶ Pa).

A particularly preferred method for preparing a secondary diamine from adiimine is to place the diimine, hydrogenation catalyst (especiallysulfided platinum on carbon) and solvent in a reaction vessel, and thento seal the reaction vessel under hydrogen gas pressure. The vessel isthen heated as desired while the reaction mixture is stirred.

B. Process for Forming a Secondary Diamine Using an Acid Ion ExchangeResin and a Hydrogenation Agent Together

Secondary diamines can be prepared in one step by mixing together, inthe same reaction zone, a ketone or aldehyde, a primary diamine, an acidion exchange resin, and a hydrogenation agent. Normally, during this onestep preparation of a secondary diamine from a primary diamine, thetemperature is kept in the range of about 20° C. to about 140° C.;preferably, the temperature is in the range of about 50° C. to about130° C. More preferably, the temperature is in the range of about 80° C.to about 130° C. When hydrogen and a hydrogenation catalyst are used,the hydrogen gas pressure is preferably in the range of about 14 psi toabout 300 psi (9.65×10⁴ to 2.07×10⁶ Pa); more preferably, the pressureis in the range of about 50 psi to about 150 psi (3.45×10⁵ to 1.03×10⁶Pa). Reaction times on the laboratory scale are on the order of abouttwo hours to about eight hours. On the plant scale, reaction times areon the order of about seven hours to about twenty-four hours.

C. Process for Forming a Secondary Diamine Using Sulfided Platinum onCarbon and/or Sulfided Palladium on Carbon

Another way to prepare secondary diamines in one step is by mixingtogether at least one ketone or aldehyde, hydrogen, a hydrogenationcatalyst which is sulfided platinum on carbon, sulfided palladium oncarbon, or a mixture thereof, and at least one primary diamine. Thepressure and temperature conditions for this process vary with thenature of the primary diamine used in the process. As is well known inthe art, aliphatic primary diamines generally react more readily incomparison to aromatic primary diamines, and thus gentler conditions canbe used with aliphatic diamines, although some aliphatic primarydiamines with substituents in close proximity to the amino group mayrequire more forcing conditions. Similarly, it is known that aromaticprimary diamines in which at least one position ortho to each aminogroup has a hydrogen atom as a substituent are more reactive thanaromatic primary diamines in which each position ortho to an amino groupbears a hydrocarbyl group, and thus more forcing conditions aretypically necessary for the aromatic primary diamines in which eachposition ortho to an amino group bears a hydrocarbyl group. To date, inthe practice of the invention, this process has yielded secondarydiamines; formation of tertiary diamines has not been observed.

When the primary diamine is an aromatic primary diamine in which atleast one position ortho to each amino group has a hydrogen atom as asubstituent, the process is conducted at a temperature in the range ofabout 20° C. to about 120° C. and at a pressure in the range of about 14to about 125 pounds per square inch (9.65×10⁴ to 8.62×10⁵ Pa).Preferably, temperatures are in the range of about 20° C. to about 80°C. and pressures are preferably in the range of about 50 to about 125pounds per square inch (3.45×10⁵ to 8.62×10⁵ Pa).

When the primary diamine is an aromatic primary diamine in which eachposition ortho to an amino group bears a hydrocarbyl group (i.e., theprimary diamine is a more preferred aromatic primary diamine), theprocess is conducted at a temperature in the range of about 22° C. toabout 140° C. and at a pressure in the range of about 14 to about 150pounds per square inch (9.65×10⁴ to 1.03×10⁶ Pa). Preferably,temperatures are in the range of about 50° C. to about 130° C. andpressures are preferably in the range of about 50 to about 125 poundsper square inch (3.45×10⁵ to 8.62×10⁵ Pa). Temperatures toward thehigher end of these ranges are preferred because the reaction rates areusually faster. More particularly, when employing temperatures in thelower end of the range, e.g., in the range of about 22° C. to about 50°C., the process tends to produce a mixture of mono-substituted aromaticdiamine and bis-substituted aromatic diamine. As the temperature isincreased, e.g., to a temperature in the range of about 50° C. to about130° C., greater amounts of the bis-substituted aromatic diamine areformed. Here, the term “mono-substituted aromatic diamine” refers to anaromatic diamine in which one amino group is secondary (i.e.,substituted) and in which the other amino group remains a primary aminogroup. Similarly, the term “bis-substituted aromatic diamine” refers toan aromatic diamine in which both amino groups are secondary.

When the primary diamine is an aliphatic primary diamine, the process isconducted at a temperature in the range of about 20° C. to about 140° C.and at a pressure in the range of about 14 to about 150 pounds persquare inch (9.65×10⁴ to 1.03×10⁶ Pa). Preferably, temperatures are inthe range of about 20° C. to about 80° C. and pressures are preferablyin the range of about 50 to about 125 pounds per square inch (3.45×10⁵to 8.62×10⁵ Pa).

A particularly preferred method for preparing a secondary diamine is toplace the primary diamine, sulfided platinum on carbon and/or sulfidedpalladium on carbon, and solvent in a reaction vessel, and then to sealthe reaction vessel under hydrogen gas pressure. The vessel is thenheated as desired while the reaction mixture is stirred. On thelaboratory scale, reaction times are typically about five hours to abouttwenty hours.

Workup and Recovery from the Processes of the Invention

The diimines produced by the processes of this invention are usuallyliquids. The diimine can be isolated if desired. Methods for separatingliquids that are well known in the art can be employed to separate atleast a portion of the diimine from the other components of the reactionmixture. Such methods include, for example, chromatography anddistillation. Of course, the diimine need not be isolated from thereaction mixture; instead, the diimine can be further reacted, forexample, to form a secondary diamine. The secondary diamines produced bythe processes of this invention are usually liquids, and may be isolatedas just described for a diimine, or used in non-isolated form. For thesecondary diamines, distillation is a preferred separation method.

It is generally economical to recover and recycle excess ketone oraldehyde, particularly when the ketone or aldehyde is used in enoughexcess to act as a solvent for the reaction mixture. Separation of theketone or aldehyde from the reaction mixture can be performed bydistillation, with separation of aqueous portions of any azeotropesencountered, or with decantation of the aqueous layer followed bydistillation of the ketone or aldehyde layer. Once at least a portion ofthe product diimine or secondary diamine has been removed from thereaction mixture, unreacted starting materials can be recycled to thereactor to form a portion of the feed stock.

Products of the Processes of the Invention

When a more preferred aromatic primary diamine of the invention (i.e.,an aromatic primary diamine which either is in the form of one phenylring having two amino groups on the ring, which amino groups are meta orpara relative to each other, and in which each position ortho to anamino group bears a hydrocarbyl group, or is in the form of two phenylrings connected by an alkylene bridge and having one amino group on eachring, and in which each position ortho to an amino group bears ahydrocarbyl group) is used, an aromatic diimine or an aromatic secondarydiamine corresponding to an aromatic diimine or an aromatic-secondarydiamine listed above as a composition of the invention is produced.

A. Aromatic diimines

Aromatic diimines which are not compositions of the present inventionthat can be produced by the processes of the invention include, but arenot limited to, N,N′-diisopropylidene-1,2-benzenediamine,N,N′-di-sec-butylidene-1,3-benzenediamine,N,N′-di(3-hexylidene)-1,4-benzenediamine,N,N′-dicyclopentylidene-4-ethyl-1,2-benzenediamine,N,N′-di-sec-butylidene-(4-tert-butyl-1,3-benzenediamine),N,N′-di(1-cycloproylethylidene)-2-pentyl-1,4-benzenediamine,N,N′-di(undecylidene)-(4-methyl-5-heptyl-1,3-benzenediamine),N,N′-di(2-cyclopentenylidene)-4,6-di-n-propyl-1,3-benzenediamine,N,N′-di-sec-butylidene-2,3-diethyl-1,4-benzenediamine,N,N′-di(2-butenylidene)-4,5,6-trihexyl-1,3-benzenediamine,N,N′-di(2,5-dimethylcyclopentylidene)-2,2′-methylenebis(benzeneamine),N,N′-dimenthylidene-2,3′-methylenebis(benzeneamine),N,N′-diisopropylidene-2,4′-methylenebis(benzeneamine),N,N′-di-sec-butylidene-3,3′-methylenebis(benzeneamine),N,N′-di(3-methyl-2-cyclohexenylidene)-3,4′-methylenebis(benzeneamine),N,N′-di(3,3-dimethyl-2-butylidene)-4,4′-methylenebis(benzeneamine),N,N′-di(3-pentylidene)-4,4′-(1,2-ethanediyl)bisbenzeneamine,N,N′-di(undecylidene)-3,4′-(1,3-propanediyl)bis(benzeneamine),N,N′-di(2,4-dimethyl-3-pentylidene)-2,2′-methylenebis(5-tert-butylbenzeneamine),N,N′-di(phorylidene)-3,3′-methylenebis(5-pentylbenzeneamine),N,N′-di(3-methylbutylidene)-3,3′-methylenebis(6-isopropylbenzeneamine),N,N′-di(2-heptylidene)-4,4′-methylenebis(2-methylbenzeneamine),N,N′-dimenthylidene-4,4′-methylenebis(3-sec-butylbenzeneamine),N,N′-di(1-cyclopentylethylidene)-4,4′-(1,2-ethanediyl)bis(2-methylbenzeneamine),andN,N′-di(1-penten-3-ylidene)-4,4′-methylenebis(2,3-di-sec-butylbenzeneamine).

B. Aromatic Secondary Diamines

Aromatic secondary diamines which are not compositions of the presentinvention that can be produced by the processes of the inventioninclude, but are not limited to, N,N′-diisopropyl-1,2-benzenediamine,N,N′-di-sec-butyl-1,3-benzenediamine,N,N′-di(2-butenyl)-1,4-benzenediamine,N,N′-dicyclopentyl-(4-ethyl-1,2-benzenediamine),N,N′-di-sec-butyl-(4-tert-butyl-1,3-benzenediamine),N,N′-di(1-cyclopropylethyl)-2-pentyl-1,4-benzenediamine,N,N′-di(4-hexyl)-(4-methyl-5-heptyl-1,3-benzenediamine),N,N′-dicyclopentyl-4,6-di-n-propyl-1,3-benzenediamine,N,N′-di-sec-butyl-(2,3-diethyl-1,4-benzenediamine),N,N′-di(1-penten-3-yl)-4,5,6-trihexyl-1,3-benzenediamine,N,N′-di(3-hexyl)-2,2′-methylenebis(benzeneamine),N,N′-di(2-cyclopentenyl)-2,3′-methylenebis(benzeneamine),N,N′-diisopropyl-2,4′-methylenebis(benzeneamine),N,N′-di-sec-butyl-3,3′-methylenebis-(benzeneamine),N,N′-di(3-methyl-2-cyclohexenyl)-3,4′-methylenebis(benzeneamine),N,N′-di(3,3-dimethyl-2-butyl)-4,4′-methylenebis(benzeneamine),N,N′-di(10-undecenyl)-4,4′-(1,2-ethanediyl)bisbenzeneamine,N,N′-di(phoryl)-3,4′-(1,3-propanediyl)bis(benzeneamine),N,N′-di(2,4-dimethyl-3-pentyl)-2,2′-methylenebis(5-tert-butylbenzeneamine),N,N′-di(2,5-dimethylcyclopentyl)-3,3′-methylenebis(2-methylbenzeneamine),N,N′-di(isophoryl)-3,3′-methylenebis(5-pentylbenzeneamine),N,N′-di(2-hexyl)-3,3′-methylenebis(6-isopropylbenzeneamine),N,N′-dicyclohexyl-4,4′-methylenebis(3-sec-butylbenzeneamine),N,N′-di(1-cyclopentylethyl)-4,4′-(1,2-ethanediyl)bis(2-methylbenzeneamine),N,N′-diisopropyl-3,3′-methylenebis(2,4-dipentylbenzeneamine),N,N′-di-sec-butyl-3,3′-methylenebis(5,6-diisopropylbenzeneamine), andN,N′-di(menthyl)-4,4′-methylenebis(2,3-di-sec-butylbenzeneamine).

C. Aliphatic Diimines

Aliphatic diimines that can be produced by the processes of theinvention include, but are not limited to,N,N′-diisopropylidene-ethylenediamine,N,N′-di-sec-butylidene-1,2-diaminopropane,N,N′-di(2-butenylidene)-1,3-diaminopropane,N,N′-di(1-cyclopropylethylidene)-1,5-diaminopentane,N,N′-di(3,3-dimethyl-2-butylidene)-1,5-diamino-2-methylpentane,N,N′-di-sec-butylidene-1,6-diaminohexane,N,N′-di(3-pentylidene)-2,5-dimethyl-2,5-hexanediamine,N,N′-di(4-hexylidene)-1,2-diaminocyclohexane,N,N′-dicyclohexylidene-1,3-diaminocyclohexane,N,N′-di(1-cyclobutylethylidene)-1,4-diaminocyclohexane,N,N′-di(2,4-dimethyl-3-pentylidene)-1,3-cyclohexanebis(methylamine),N,N′-di(1-penten-3-ylidene)-1,4-cyclohexanebis(methylamine),N,N′-diisopropylidene-1,7-diaminoheptane,N,N′-di-sec-butylidene-1,8-diaminooctane,N,N′-di(2-pentylidene)-1,10-diaminodecane,N,N′-di(3-hexylidene)-1,12-diaminododecane,N,N′-di(3-methyl-2-cyclohexenylidene)-1,2-diaminopropane,N,N′-di(2,5-dimethylcyclopentylidene)-1,4-diaminobutane,N,N′-di(isophorylidene)-1,5-diaminopentane,N,N′-di(menthylidene)-2,5-dimethyl-2,5-hexanediamine,N,N′-di(undecylidene)-1,2-diaminocyclohexane,N,N′-di-2-(4-methylpentylidene)-isophoronediamine, andN,N′-di(5-nonylidene)-isophoronediamine.

D. Aliphatic Secondary Diamines

Aliphatic secondary diamines that can be produced by the processes ofthe invention include, but are not limited to,N,N′-diisopropylethylenediamine, N,N′-di-sec-butyl-1,2-diaminopropane,N,N′-di(2-butenyl)-1,3-diaminopropane,N,N′-di(1-cyclopropylethyl)-1,5-diaminopentane,N,N′-di(3,3-dimethyl-2-butyl)-1,5-diamino-2-methylpentane,N,N′-di-sec-butyl-1,6-diaminohexane, N,N′-di(3-pentyl)-2,5-dimethyl-2,5-hexanediamine, N,N′-di(4-hexyl)-1,2-diaminocyclohexane,N,N′-dicyclohexyl-1,3-diaminocyclohexane,N,N′-di(1-cyclobutylethyl)-1,4-diaminocyclohexane,N,N′-di(2,4-dimethyl-3-pentyl)-1,3-cyclohexanebis(methylamine),N,N′-di(1-penten-3-yl)-1,4-cyclohexanebis(methylamine),N,N′-diisopropyl-1,7-diaminoheptane,N,N′-di-sec-butyl-1,8-diaminooctane,N,N′-di(2-pentyl)-1,10-diaminodecane,N,N′-di(3-hexyl)-1,12-diaminododecane,N,N′-di(3-methyl-2-cyclohexenyl)-1,2-diaminopropane,N,N′-di(2,5-dimethylcyclopentyl)-1,4-diaminobutane,N,N′-di(isophoryl)-1,5-diaminopentane,N,N′-di(menthyl)-2,5-dimethyl-2,5-hexanediamine,N,N′-di(undecyl)-1,2-diaminocyclohexane,N,N′-di-2-(4-methylpentyl)-isophoronediamine, andN,N′-di(5-nonyl)-isophoronediamine.

Formulations of the Invention

When the aromatic secondary diamines which are compositions of theinvention are used as chain extenders in the preparation ofpolyurethane, polyurea, or polyurethane-urea polymers, they are used inplace of the chain extenders that have previously been used in suchprocesses, or they are used in conjunction with one or more known chainextenders, e.g., aromatic primary diamines such as those mentionedabove; the aromatic polyamines of U.S. Pat. Nos. 3,428,610, 4,218,543,4,595,742, and 4,631,298; polyhydroxyalkanes containing 2-6 carbons and2-3 hydroxyl groups, such as ethylene glycol, the 1,2- and 1,3-propyleneglycols, 1,4-, 1,2-, and 2,3-butanediols, 1,5-pentanediol, neopentylglycol, 1,6-hexanediol, glycerol, 1,2,4-butanetriol, 1,2,6-hexanetriol;and mixtures of any two or more of the foregoing. Thus, the chainextender or mixture of chain extenders is reacted with an organicpolyisocyanate and an active hydrogen-containing organic compound orwith a prepolymer thereof having a free —NCO content of at least about0.1% by weight to form the desired polymer. Whether the aromaticsecondary diamines of the invention are used in place of or instead inconjunction with other chain extenders depends in part on the desiredphysical properties of the end product. Examples of isocyanates andactive hydrogen-containing organic compounds that can be used are taughtin, for example, U.S. Pat. No. 4,595,742.

When the aromatic secondary diamines which are compositions of thisinvention are to be used as curing agents for epoxy resins, they areused in place of the curing agents that have previously been used tocure such resins, or they are used in conjunction with one or more knowncuring agents, e.g., aromatic polyamines and/or polyhydroxyalkanes.Whether the aromatic secondary diamines of the invention are used inplace of or instead in conjunction with other curing agents depends inpart on the desired physical properties of the end product. The epoxyresin may be any epoxy resin, i.e., it may be saturated or unsaturated,aliphatic, cycloaliphatic, aromatic, or heterocyclic. Examples of suchresins are taught in Lee et al., Handbook of Epoxy Resins, McGraw-Hill(New York), 1967.

Formulations of the invention are made from at least one polyol and/orat least one polyetheramine (sometimes referred to as anamine-terminated polyol), at least one isocyanate, and at least onearomatic secondary diamine which a composition of the invention; thatis, an aromatic secondary diamine in which each amino hydrocarbyl grouphas at least two carbon atoms, wherein each position ortho to an aminogroup bears a hydrocarbyl group, and which aromatic secondary diamine iseither in the form of one phenyl ring having two amino groups on thering, which amino groups are meta or para relative to each other or isin the form of two phenyl rings connected by an alkylene bridge andhaving one amino group on each ring. As is well known in the art, othercomponents may also be included in the formulations, such as one or moreflame retardants, thermal stabilizers, and/or surfactants.

In the methods of the invention, a polyurethane, polyurea, orpolyurea-urethane is made by blending at least one polyol and/or atleast one polyetheramine, at least one isocyanate, and at least onearomatic secondary diamine which a composition of the invention; thatis, an aromatic secondary diamine in which each amino hydrocarbyl grouphas at least two carbon atoms, wherein each position ortho to an aminogroup bears a hydrocarbyl group, and which aromatic secondary diamine iseither in the form of one phenyl ring having two amino groups on thering, which amino groups are meta or para relative to each other or isin the form of two phenyl rings connected by an alkylene bridge andhaving one amino group on each ring. Usually, the polyol orpolyetheramine, aromatic secondary diamine, and when used, optionalingredients, are blended together to form a first mixture, followed byblending this first mixture with the isocyanate to form a secondmixture. This second mixture is allowed to cure.

The following examples are presented for purposes of illustration, andare not intended to impose limitations on the scope of this invention.

EXAMPLE 1

4,4′-Methylenebis(2,6-diethylbenzeneamine) (4.0 g), Pt(S)/C (0.2 g),sulfonated divinylbenzene/styrene copolymer (0.2 g; H ion form, sold asAmberlyst-15 by Rohm and Haas Company, Philadelphia, Pa.), and methylethyl ketone (50 g) were charged into a 100 mL metal autoclave at 22° C.The closed autoclave was purged 3 times with 125 psig (9.63×10⁵ Pa) ofH₂ at 22° C. to remove traces of air. The reaction mixture was thenheated at 95° C. under 125 psig (9.63×10⁵ Pa) of H₂ for 3 hours (untilno further H₂ uptake was observed). The product mixture was cooled to22° C. and degassed. A diluted product sample was analyzed by gaschromatography (GC; 180° C. for 5 minutes at 10° C. per minute rate;final temperature, 270° C.). The GC data (normalization method) showed100% conversion of 4,4′-methylenebis(2,6-diethylbenzeneamine) and a 94%yield of N,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine).NMR analysis (with internal standard) of a neat product sample showed apurity of 94.75%.

EXAMPLE 2

Diethyl(methyl)-1,3-benzenediamine, as a mixture of its2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers (10.0 g;Ethacure® 100, Albemarle Corporation), Pt(S)/C (0.5 g), Amberlyst-15(0.5 g), and methyl ethyl ketone (50 g) were charged into a 100 mL metalautoclave at 22° C. The closed autoclave was purged 3 times with 125psig (9.63×10⁵ Pa) of H₂ at 22° C. to remove traces of air. The reactionmixture was then heated at 120° C. under 125 psig (9.63×10⁵ Pa) of H₂for 5.5 hrs (until no further H₂ uptake was observed). The productmixture was cooled to 22° C. and degassed. A diluted product sample wasanalyzed by GC (100° C. for 5 minutes at 10° C. per minute rate; finaltemperature, 270° C.). The GC data (normalization method) showed 100%conversion of diethyl(methyl)-1,3-benzenediamine, and a 96.5% yield ofN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine].

EXAMPLE 3

4,4′-Methylenebis(2,6-diethylbenzeneamine) (3 g), Pt(S)/C (0.3 g),Amberlyst-15 (0.3 g), methyl ethyl ketone (25 g), and tetrahydrofuran(THF; 25 g) were charged into a 100 mL metal autoclave at 22° C. Theclosed autoclave was purged 3 times with 90 psig (7.22×10⁵ Pa) of H₂ at22° C. The reaction mixture was then heated at 100-120° C. under 125psig (9.63×10⁵ Pa) of H₂ for 5 hrs (until no further H₂ uptake wasobserved). The product mixture was cooled to 22° C. and degassed. Adiluted product sample was analyzed by GC (180° C. for 5 minutes at 10°C. per minute rate; final temperature, 270° C.). The GC data(normalization method) showed 100% conversion of4,4′-methylenebis(2,6-diethylbenzeneamine), and an 86% yield ofN,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine).

EXAMPLE 4

Diethyl(methyl)-1,3-cyclohexanediamine, as a mixture of its2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers was made byhydrogenating diethyl(methyl)-1,3-benzenediamine, as a mixture of its2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers (Ethacure® 100)according to known procedures; see for example U.S. Pat. No. 4,161,492.

Diethyl(methyl)-1,3-cyclohexanediamine, as a mixture of its2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers (3.0 g), Pt(S)/C(0.4 g), Amberlyst-15 (0.4 g), and methyl ethyl ketone (45 g) werecharged into a 100 mL metal autoclave at 22° C. The closed autoclave waspurged 3 times with 125 psig (9.63×10⁵ Pa) of H₂ at 22° C. to removetraces of air. The reaction mixture was then heated at 130° C. under 125psig (9.63×10⁵ Pa) of H₂ for 6 hrs (until no further H₂ uptake wasobserved). The product mixture was cooled to 22° C. and degassed. Adiluted product sample was analyzed by GC (100° C. for 5 minutes at 10°C. per minute rate; final temperature, 270° C.). The GC data(normalization method) showed 100% conversion ofdiethyl(methyl)-1,3-cyclohexanediamine, and a 95-97% yield ofN,N′-di-sec-butyl-[diethyl(methyl)-1,3-cyclohexanediamine].

EXAMPLE 5

Diethyl(methyl)-1,3-cyclohexanediamine, as a mixture of its2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers was made asdescribed in Example 4. Diethyl(methyl)-1,3-cyclohexanediamine, as amixture of its 2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers(10 g), Pt(S)/C (0.5 g), Amberlyst-15 (0.5 g), and acetone (50 g) werecharged into a 100 mL metal autoclave at 22° C. The closed autoclave waspurged 3 times with 125 psig (9.63×10⁵ Pa) of H₂ at 22° C. to removetraces of air. The reaction mixture was then heated at 110-130° C. under125 psig (9.63×10⁵ Pa) of H₂ for 8 hrs (until no further H₂ uptake wasobserved). The product mixture was cooled to 22° C. and degassed. Adiluted product sample was analyzed by GC (100° C. for 5 minutes at 110°C. per minute rate; final temperature, 270° C.). The GC data(normalization method) showed 100% conversion ofdiethyl(methyl)-1,3-cyclohexanediamine, and a 95-97% yield ofN,N′-diisopropyl-[diethyl(methyl)-1,3-cyclohexanediamine].

EXAMPLE 6

A two-liter three neck round bottom flask was equipped with a heatingmantle, a thermocouple, a glass stopper and a condenser.4,4′-Methylenebis(2,6-diethylbenzeneamine) (200 g, 0.644 mol) andacetone (200 mL, 158 g, 2.72 mol) were added to the flask. After the4,4′-methylenebis(2,6-diethylbenzeneamine) had dissolved in the acetone,molecular sieves (200 g) and Amberlyst-15 (20 g) were added to theflask. Molecular sieves were used to remove water as it formed in thereaction. The mixture was heated to reflux. Samples were periodicallytaken and analyzed by GC. After 24 hours, 18% of the starting diamineremained. The reaction mixture was filtered, and returned to thereaction flask. Fresh molecular sieves (200 g) and fresh Amberlyst-15(20 g) were added to the filtered mixture in the reaction flask. Moreacetone (170 mL) was also added to the reaction mixture. GC analysis ofthis mixture showed 94.4 area %N,N′-diisopropylidene-4,4′-methylenebis(2,6-diethylbenzeneamine), 3.7area % N-isopropylidene-4,4′-methylenebis(2,6-diethylbenzeneamine), and0.2 area % 4,4′-methylenebis(2,6-diethylbenzeneamine).

N,N′-diisopropylidene-4,4′-methylenebis(2,6-diethylbenzeneamine) (2.6 g)and Pt(S)/C (0.35 g) were added to a mixture of ethanol (20 g) and ethylacetate (20 g) in an autoclave. The closed autoclave was purged 3 timeswith 125 psig (9.63×10⁵ Pa) of H₂ at 22° C. to remove traces of air. Themixture was kept at 22° C. and 0-125 psi (0 to 8.62×10⁵ Pa) of H₂ for1.2 hours, forming the correspondingN,N′-diisopropyl-4,4′-methylenebis(2,6-diethylbenzeneamine) in 70%yield, with 25% of the diimine underhydrogenated. Conversion of thediimine was 95%.

EXAMPLE 7

Diethyl(methyl)-1,3-benzenediamine (Ethacure® 100; 30 g, 0.17 mol),acetone (150 mL, 117 g, 2.0 mol), Amberlyst-15 (2 g), and molecularsieves (64.1 g) were added to a one-pint bottle. Occasionally, thebottle was rolled and the mixture was analyzed by GC. After 19 days, GCanalysis showed 88.5 area % ofN,N′-diisopropylidene-[diethyl(methyl)-1,3-benzenediamine] (includesboth isomers) and 10.1 area % ofN-isopropylidene-[diethyl(methyl)-1,3-benzenediamine] (includes threeisomers).

N,N′-diisopropylidene-[diethyl(methyl)-1,3-benzenediamine] (3.17 g) andPt(S)/C (0.3 g) were added to a mixture of ethanol (20 g) and ethylacetate (20 g) in an autoclave. The closed autoclave was purged 3 timeswith 125 psig (9.63×10⁵ Pa) of H₂ at 22° C. to remove traces of air. Themixture was kept at 22° C. and 0-125 psi (0 to 8.62×10⁵ Pa) of H₂ for1.2 hours, forming the correspondingN,N′-diisopropyl-[diethyl(methyl)-1,3-benzenediamine] in 94% yield. Sixpercent of the diimine was underhydrogenated; conversion of the diiminewas 100%.

EXAMPLE 8

A two-liter three neck round bottom flask was equipped with a magneticstirrer, a heating mantle, a thermocouple, a glass stopper and a DeanStark trap fitted with a condenser.4,4′-Methylenebis(2,6-diethylbenzeneamine) (310.5 g, 1.00 mol) andmethyl ethyl ketone (450 mL, 350 g, 4.85 mol) were added to the flask.This mixture was stirred at 40° C. to dissolve the4,4′-methylenebis(2,6-diethylbenzeneamine). Hexanes (300 mL) andAmberlyst-15 (15.54 g) were added to the flask. The mixture was heatedto reflux, and water was removed as an azeotrope in the Dean Stark trap.Samples were periodically taken and analyzed by gas chromatography (GC).N,N′-di-sec-butylidene-4,4′-methylenebis(2,6-diethylbenzeneamine) wasformed in 94.7% yield. GC results are summarized in Table 1; units forthe diamine, monoimine, and diimine are GC area percent.

N,N′-di-sec-butylidene-4,4′-methylenebis(2,6-diethylbenzeneamine) (22.53g) and Pt(S)/C (2.65 g) were added to acetone (34.0 g) in an autoclave.The closed autoclave was purged 3 times with 125 psig of H₂ (9.63×10⁵Pa) at 22° C. The mixture was kept at 21° C. and 125 psi (8.62×10⁵ Pa)of H₂ for 6.5 hours, forming the correspondingN,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine)quantitatively.

TABLE 1 Time at reflux Water collected Diamine Monoimine Diimine  0 hr  0 g 95.8 4.0 0  3 hr  9.0 g 64.6 31.6 3.6 19 hr 33.0 g 4.5 33.1 62.122 hr 36.0 g 2.0 24.9 72.9 26 hr 39.6 g 1.1 16.8 81.8 26 hr 39.7 g 0.714.8 84.3 29 hr 41.1 g 0.3 9.6 89.9 49 hr 42.3 g 0.5 4.4 94.7

EXAMPLE 9

A two-liter three neck round bottom flask was equipped with a magneticstirrer, a heating mantle, a thermocouple attached to a thermowatch, anda condenser fitted with a nitrogen inlet.3,5-Diethyl(methyl)-1,3-benzenediamine (Ethacure® 100; 100 g, 0.562 mol)and methyl ethyl ketone (200 g, 2.77 mol) were added to the flask.Amberlyst-15 (20 g) and molecular sieves (200 g) were added to theflask. The mixture was heated to reflux; the pot temperature was 85° C.Samples were periodically taken and analyzed by GC. Table 2 summarizesthe GC area % conversion over time. After 6 hours, an additional 50 g ofmolecular sieves were added. The reaction product mixture was filteredthrough a sintered glass funnel to remove Amberlyst-15 and the molecularsieves. Methyl ethyl ketone was removed via distillation to give 138 gof N,N′-di-sec-butylidene-[diethyl(methyl)-1,3-benzenediamine].

N,N′-di-sec-butylidene-[diethyl(methyl)-1,3-benzenediamine] (28 g) andPt(S)/C (2.8 g) were added to acetone (30 g) in an autoclave. The closedautoclave was purged 3 times with 125 psig (9.63×10⁵ Pa) of H₂ at 22° C.The mixture was kept at 21° C. and 125 psi (8.62×10⁵ Pa) of H₂ for 12hours, forming the correspondingN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine] quantitatively.

TABLE 2 Diamine Monoimine Diimine Isomer: 2,4- 2,6- 2,4- 2,4- 2,6- 2,4-2,6- Time at reflux 0.25 hr   48.8 6.4 10.3 14.7 12.3 2.4 2.3  3 hr 3.60.2 14.1 27.7 4.9 31.1 15.9  6 hr 0.3 — 6.0 15.4 1.4 56.2 18.9  7 hr 0.3— 4.5 11.5 1.2 62.0 18.8 12 hr 0.2 — 3.9 6.8 1.5 67.5 18.1 28 hr — — 2.72.6 1.1 72.7 18.2 Final product — — 2.4 2.3 0.9 72.9 18.2

EXAMPLE 10

The first run (Run 1) was performed in a 2 liter Parr reactor, and Runs2-5 were done in a 10 gallon stainless steel reactor (AutoclaveEngineers, Erie, Pa.). Diethyl(methyl)-1,3-benzenediamine, as a mixtureof its 2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers (Ethacure®100, Albemarle Corporation) was charged to the reactor, followed bymethyl ethyl ketone (MEK), then Pt(S)/C, and then Amberlyst-15. Amountsof reagents used in each run are listed in Table 3. The reactor wassealed and purged three times with H₂ and then the reactor was pressuredwith H₂ to about 75 to 130 psig (6.18×10⁵ to 9.98×10⁵ Pa). The reactorcontents were stirred at 115 to 130° C. for 9 to 24 hours at 75 to 135psig (6.18×10⁵ to Pa). Specific pressure and temperature ranges for eachrun are listed in Table 3. The reaction mass in the reactor was cooled,and the reactor was vented and purged with nitrogen 3 times. Thereaction masses from the 10 gallon reactor were pressured though a pairof 10-inch (25.4 cm) 0.5-micron cartridge filters in parallel to removethe Pt(S)/C and Amberlyst-15. Due to the higher concentration in thereaction masses from Runs 2 and 3, additional MEK was added beforepressuring the reaction mass through the cartridge filters to reduce thetime required for the filtration (removal of the catalysts). Results aresummarized in Table 3. Conversion, yield, and partially reacted amountsreported in Table 3 were determined by GC (100° C. for 5 minutes at 10°C. per minute rate; final temperature, 270° C.).

The reaction masses from Runs 2, 3, 4, and 5, and 1000 g of the finalreaction mass from Run 1 were combined into a 100 liter reactor as spacepermitted. Each reaction mass was filtered with a 10-inch, 0.5-microncartridge filter into the 100 liter reactor. The bulk of the MEK wasremoved at atmospheric pressure. The combined product was distilled atless than 1 torr (133 Pa) at 134 to 141° C. to give 2.189 g of aforecut, 30.0 kg of a main cut, and 2370 g of dark distillation potbottoms. By GC area %, it appeared that most of the distillation potbottoms were the product,N,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine]. The distillationpot bottoms were flashed twice using a wiped film evaporator to give anadditional 2.254 kg of product which was added to the 30.0 kg main cut.The forecut was sent back through the wiped film evaporator twice; thefirst pass was to remove the lower boiling impurities and the secondpass was to obtain additional product (1408 g). This additional productwas combined with the 30 kg and 2.254 kg product to give 33.6 kg of thefinal product as a yellow liquid (94% yield, not corrected for purity).The composition of this material was 78.85 area %N,N′-di-sec-butyl-[2,4-diethyl-6-methyl-1,3-benzenediamine] and 16.67area % N,N′-di-sec-butyl-[4,6-diethyl-2-methyl-1,3-benzenediamine].

TABLE 3 Compound Run 1 Run 2 Run 3 Run 4 Run 5 Ethacure ® 100 252 g 4756g 5064 g 3980 g 4020 g MEK 1.0 kg 14.01 kg 15.09 kg 16.57 kg 16.5 kgPt(S)/C 12.5 g 254 g 256 g 200 g 204 g Amberlyst-15 12.5 g 250 g 250 g200 g 200 g MEK added 5.0 kg 5.0 kg none none after reaction MEK rinse5.0 kg 4.9 kg 4.96 kg 9367 kg H₂ Pressure 76-125 psig 120-127 psig120-132 psig 119-120 psig 120-193 psig (6.25 × 10⁵-9.63 × 10⁵ (9.29 ×10⁵-9.77 × 10⁵ (9.29 × 10⁵-1.01 × 10⁶ (9.22 × 10⁵-9.29 × 10⁵ (9.29 ×10⁵-1.43 × 10⁶ Pa) Pa) Pa) Pa) Pa) Temperature 121-132° C. 126-133° C.118-130° C. 115-117° C. 125-127° C. Stirring time 24 hrs 22 hrs 19 hrs19 hrs 9 hrs Conversion 100% 100% 100% 100% 100% Yield 96.5% 94% 96.0%95.9% 95.5% Partially 3.5% 3.3% 1.7% 1.8% 1.7% reacted* *The partiallyreacted species found in the GC were identified as diimines(unhydrogenated) or a compound with a secondary amino group and an iminogroup (partially hydrogenated).

EXAMPLE 11

Diethyl(methyl)-1,3-benzenediamine, as a mixture of its2,4-diethyl-6-methyl- and 4,6-diethyl-2-methyl-isomers (5 g; Ethacure®100, Albemarle Corporation), Pt(S)/C (0.5 g), water (1 g) and methylethyl ketone (50 g) were charged into a 100 mL metal autoclave at 22° C.The autoclave was purged 3 times with 125 psig (9.63×10⁵ Pa) of H₂ at22° C. The reaction mixture was then heated at 130° C. under 125 psig(9.63×10⁵ Pa) of H₂. After 30-45 minutes, H₂ uptake was observed. Thereaction mixture was stirred at 130° C. for 8 hours (until no further H₂uptake was observed). The product mixture was cooled to 22° C. anddegassed. A diluted product sample was analyzed by GC (100° C. for 5minutes at 10° C. per minute rate; final temperature, 270° C.). The GCdata (normalization method) showed 100% conversion ofdiethyl(methyl)-1,3-benzenediamine, and an 88.8% yield ofN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine].

EXAMPLE 12

Isophorone diamine (10 g), 5-nonanone (20 g), Amberlyst-15 (0.3 g), andPt(S)/C (0.7 g) were charged into a 100 mL metal autoclave at 22° C. Theautoclave was purged 3 times with 111 psig (8.67×10⁵ Pa) of H₂ at 22° C.The reaction mixture was then heated to and stirred at 116-121° C. under111 psig (8.67×10⁵ Pa) of H₂ for 10 hours. GC indicated incompletehydrogenation, so additional Amberlyst-15 (0.3 g) and Pt(S)/C (0.5 g)were added to the autoclave. The reaction mixture was stirred at110-130° C. under 93 psig (7.43×10⁵ Pa) of H₂ for 24 hours. GC indicated100% conversion of the starting materials, and a 93.6% yield of theproduct, N,N′-di-5-nonyl-isophoronediamine.

EXAMPLE 13

4,4′-Methylenebis(benzeneamine) (1.98 g, 10 mmol), acetone (10.0 g, 172mmol), Pt(S)/C (0.2 g), and toluene (50.0 g) were charged into reactor.The reactor was purged 3 times with 110 psig (8.60×10⁵ Pa) of H₂ at 22°C. The reaction mixture was then stirred at 60° C. under 110 psig(8.60×10⁵ Pa) of H₂ for 2 hours. GC (conditions: 180° C./5 miminutes/10°C.-minutes rate/270° C./RT=9.37 minutes) showed 100% conversion of4,4′-methylenebis(benzeneamine), and a 97% yield ofN,N′-diisopropyl-4,4′-methylenebis(benzeneamine). The structure of theproduct was confirmed by GC-MS. No tertiary diamine was detected eitherby GC or by GC-MS.

EXAMPLE 14

4,4′-Methylenebis(benzeneamine) (8.0 g, 40 mmol), acetone (10.0 g, 172mmol), Pt(S)/C (0.5 g), and toluene (50.0 g) were charged into reactor.The reactor was purged 3 times with 110 psig (8.60×10⁵ Pa) of H₂ at 22°C. The reaction mixture was then stirred at 22° C. under 110 psig(8.60×10⁵ Pa) of H₂ overnight. GC (conditions: 180° C./5 minutes/10°C.-minutes rate/270° C./RT=9.37 minutes) showed 100% conversion of4,4′-methylenebis(benzeneamine), and a 98% yield ofN,N′-diisopropyl-4,4′-methylenebis(benzeneamine). The structure of theproduct was confirmed by GC-MS. No tertiary diamine was detected eitherby GC or by GC-MS.

EXAMPLE 15

Polyurethane formulations containing isocyanate (15.2% NCO, Rubinate®9480, Huntsman Chemical), a polyol (a triol with molecular weight 5000,Voranol® 4703, Dow Chemical Company), a mixture of2,4-diethyl-6-methyl-1,3-benzenediamine and4,6-diethyl-2-methyl-1,3-benzenediamine (Ethacure® 100, AlbemarleCorporation), N,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine],and dibutyl tin dilaurate (DABCO® T-12, Air Products and Chemicals,Inc., Allentown, Pa.) were prepared; one formulation was preparedwithout N,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine], forcomparative purposes. All ingredients except the isocyanate were mixedtogether in a blender for five minutes and then degassed in an oven;amounts of the components in this mixture are listed in Table 4. Themixture was placed in one barrel of a two-barrel syringe; the isocyanatewas placed in the other barrel. The syringe contents were blended bypushing them through a static mixer onto a steel plate and cured at roomtemperature. A 1:1 volume ratio of isocyanate to the mixture resultedfrom the blending of the syringe contents. The cured formulations werethen subjected to testing. Properties of the formulations are summarizedin Table 4.

TABLE 4 Component Formulation 1 Formulation 2 Formulation 3 Formulation4 Polyol 69.3 wt % 63.0 wt % 60.5 wt % 56.6 wt % Ethacure ® 100 30.5 wt% 24.5 wt % 19.5 wt % 16.5 wt % N,N′-di-sec- 0 12.4 wt % 20.0 wt % 26.8wt % butyl-[diethyl(methyl)-1,3- benzenediamine] dibutyl tin dilaurate0.1 wt % 0.1 wt % 0.1 wt % 0.1 wt % Static mixer units 48 48 48 48 Geltime (cure rate) 3 4 4 Shore D hardness, 0 sec. 49 46 42 35 Shore Dhardness, 10 sec. 43 41 36 30 Tensile strength 2940 psi 2840 psi 1850psi 1430 psi (2.03 × 10⁷ Pa) (1.96 × 10⁷ Pa) (1.28 × 10⁷ Pa) (9.9 × 10⁶Pa) Elongation 360% 400% 350% 360% Modulus (100%) 1470 psi 1250 psi 960psi 760 psi (1.0 × 10⁷ Pa) (8.6 × 10⁶ Pa) (6.6 × 10⁶ Pa) (5.2 × 10⁶ Pa)Modulus (300%) 2540 psi 2250 psi 1640 psi 1280 psi (1.8 × 10⁷ Pa) (1.6 ×10⁷ Pa) (1.1 × 10⁷ Pa) (8.8 × 10⁶ Pa) Tear strength 440 pli 350 pli 290pli 230 pli

EXAMPLE 16

Polyurea formulations containing isocyanate (14.9% NCO, Rubinate® 9480,Huntsman Chemical), Jeffamine D-2000 and Jeffamine® T-5000(amine-terminated polyols or polyetheramines, Huntsman Chemical),Ethacure® 100, andN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine] were prepared asdescribed in Example 15; one formulation was prepared withoutN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine], for comparativepurposes. Amounts of the components of the mixture that was blended withthe isocyanate in each formulation are listed in Table 5. The curedformulations were subjected to testing. Properties of the formulationsare summarized in Table 5.

TABLE 5 Component Formulation 1 Formulation 2 Formulation 3Amine-terminated 66.1 wt % 61.8 wt % 58.9 wt % polyol (Jeffamine ®D-2000) Amine-terminated 5.8 wt % 5.3 wt % 5.3 wt % polyol (Jeffamine ®T-5000) Ethacure ® 100 28.1 wt % 22.0 wt % 17.9 wt % N,N′-di-sec-butyl-0 11.0 wt % 17.9 wt % [diethyl(methyl)- 1,3-benzenediamine] Mixingtemperature 71° C. 68° C. 59° C. Gel time (cure rate) 1 sec. 5 sec. 5sec. Shore D hardness, 49 44 39 0 sec. Shore D hardness, 43 38 32 10sec. Tensile strength 1880 psi 1950 psi 1640 psi (1.30 × 10⁷ Pa) (1.33 ×10⁷ Pa) (1.13 × 10⁷ Pa) Elongation 340% 440% 420% Modulus (100%) 1180psi 950 psi 870 psi (8.1 × 10⁶ Pa) (6.6 × 10⁶ Pa) (6.0 × 10⁶ Pa) Modulus(300%) 1750 psi 1500 psi 1330 psi (1.2 × 10⁷ Pa) (1.03 × 10⁷ Pa) (9.2 ×10⁶ Pa) Tear strength 400 pli 370 pli 340 pli

EXAMPLE 17

Polyurea formulations containing isocyanate (Rubinate® 9480, HuntsmanChemical), Jeffamine® D-2000, Jeffamine® T-5000, andN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzene-diamine] were prepared asdescribed in Example 15. Amounts of the components in each formulationare listed in Table 6; the amount ofN-sec-butyl-[diethyl(methyl)-1,3-benzenediamine] listed is the amountpresent in the N,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine].The formulations were subjected to testing. Properties of theformulations are summarized in Table 6.

TABLE 6 Component Formulation 1 Formulation 2 Formulation 3 Formulation4 Formulation 5 Amine-terminated polyol 61.8 wt % 61.9 wt % 62.0 wt %61.4 wt % 61.5 wt % (Jeffamine ® D-2000) Amine-terminated polyol 5.3 wt% 5.3 wt % 5.3 wt % 5.3 wt % 5.3 wt % (Jeffamine ® T-5000) Ethacure ®100 21.9 wt % 21.8 wt % 21.9 wt % 22.5 wt % 22.4% N,N′-di-sec- 11.0 wt %11.0 wt % 10.9 wt % 10.9 wt % 10.9 wt % butyl-[diethyl(methyl)-1,3-benzenediamine] Amount of primary 0.5% 2.9% 6.0% 13.7% 21.2% aminepresent in the secondary diamine* Gel time (cure rate) 9 sec. 8 sec. 7sec. 8 sec. 10 sec. Tensile strength 1700 psi 1730 psi 1470 psi 1270 psi1120 psi (1.17 × 10⁷ Pa) (1.19 × 10⁷ Pa) (1.01 × 10⁷ Pa) (8.76 × 10⁶ Pa)(7.72 × 10⁶ Pa) Elongation 390% 400% 300% 260% 220% Modulus (100%) 940psi 950 psi 980 psi 960 psi 930 psi (6.5 × 10⁶ Pa) (6.6 × 10⁶ Pa) (6.8 ×10⁶ Pa) (6.6 × 10⁶ Pa) (6.4 × 10⁶ Pa) Modulus (300%) 1450 psi 1460 psi1510 psi 1350 psi (1.0 × 10⁷ Pa) (1.0 × 10⁷ Pa) (1.0 × 10⁷ Pa) (9.3 ×10⁶ Pa) Tear strength 370 pli 370 pli 350 pli 340 pli 330 pli *Theprimary amine is N-sec-butyl-[diethyl(methyl)-1,3-benzenediamine]; thesecondary diamine isN,N′-di-sec-butyl-[diethyl(methyl)-1,3-benzenediamine].

EXAMPLE 18

Polyurea formulations containing isocyanate (Rubinate® 9480, HuntsmanChemical), Jeffamine® D-2000, Jeffamine® T-5000, Ethacure® 100, andN,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine) wereprepared as described in Example 15. Amounts of the components in eachformulation are listed in Table 7; the amount ofN-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine) listed is theamount present in theN,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine). Theformulations were subjected to testing. Properties of the formulationsare summarized in Table 7.

TABLE 7 Formulation 1 Formulation 2 Formulation 3 ComponentAmine-terminated 57.1 wt % 51.6 wt % 41.6 wt % polyol (Jeffamine ®D-2000) Amine-terminated 5.9 wt % 5.9 wt % 5.9 wt % polyol (Jeffamine ®T-5000) Ethacure ® 100 24.3 wt % 21.2 wt % 15.6 wt %N,N′-di-sec-butyl-4,4′- 12.7 wt % 21.3 wt % 36.9 wt % methylenebis(2,6-diethylbenzeneamine) Amount of primary 3.2% 3.2% 3.2% amine present inthe secondary diamine* Property Gel time (cure rate) 7 sec. 10 sec. 15sec. Shore D hardness, 47 46 43 0 sec. Shore D hardness, 42 40 36 10sec. Tensile strength 2010 psi 2040 psi 1390 psi (1.39 × 10⁷ Pa) (1.41 ×10⁷ Pa) (9.6 × 10⁶ Pa) Elongation 350% 410% 420% Modulus (100%) 1170 psi1050 psi 810 psi (8.1 × 10⁶ Pa) (7.2 × 10⁶ Pa) (5.6 × 10⁶ Pa) Modulus(300%) 1890 psi 1680 psi 1180 psi (1.3 × 10⁷ Pa) (1.2 × 10⁷ Pa) (8.1 ×10⁶ Pa) Tear strength 425 pli 400 pli 310 pli *The primary amine isN-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine), amonosubstituted product; the secondary diamine isN,N′-di-sec-butyl-4,4′-methylenebis(2,6-diethylbenzeneamine).

Formulations similar to the those in Examples 15-18 were made withN,N′-diisopropyl-4,4′-methylenebis(benzeneamine) andN,N′-di-5-nonyl-isophoronediamine. The gel time (cure rate) for theN,N′-diisopropyl-4,4′-methylenebis(benzeneamine) formulation was 300seconds, and the gel time for the N,N′-di-5-nonyl-isophoronediamineformulation was 59 seconds. Another formulation similar to those inExamples 15-18 was made withN,N′-di-2-(4-methylpentyl)-isophoronediamine; the gel time for thisformulation was 22 seconds. Still another formulation similar to thosein Examples 15-18 was made with N,N′-di-(3,3-dimethyl-2-butyl)-TCDdiamine; the gel time for this formulation was 25 seconds. Yet anotherformulation similar to those in Examples 15-18 was made withN,N′-di-(3,3-dimethyl-2-butyl)-1,6-diaminohexane; the gel time for thisformulation was 25 seconds at room temperature. In addition, curingagents having up to about 10% (or even 15%) of the correspondingmono-secondary-diamine (in which one of the amino groups is secondaryand the other amino group is primary) have been found to be effective informulations similar to those in Examples 15-18.

EXAMPLE 19

4,4′-Methylenebis(2,6-dimethylbenzeneamine) (1.25 g), methyl ethylketone (15 g), Pt(S)/C (0.10 g), and toluene (40.0 g) were charged intoreactor. The reactor was purged 3 times with 110 psig (8.60×10⁵ Pa) ofH₂ at 22° C. The reaction mixture was then stirred at 22° C. under 110psig (8.60×10⁵ Pa) of H₂ for 4.5 hours. GC (conditions: 100° C./5minutes/10° C.-minute/270° C.) showed 35% conversion of4,4′-methylenebis(2,6-dimethylbenzeneamine). The reaction mixture wasthen stirred for 4 hours at 60° C., after which GC showed 79.5%conversion of 4,4′-methylenebis(2,6-dimethylbenzeneamine). The reactionmixture was then stirred for 11 hours at 130° C., after which GC showed100% conversion of 4,4′-methylenebis(2,6-dimethylbenzeneamine), and a96% yield ofN,N′-di-sec-butyl-4,4′-methylenebis(2,6-dimethylbenzeneamine); theremaining 4% was determined to beN-sec-butyl-4,4′-methylenebis(2,6-dimethylbenzeneamine). The product wasobserved to be water-white in color, and the structure of the productwas confirmed by GC-MS.

It is to be understood that the reactants and components referred to bychemical name or formula anywhere in this document, whether referred toin the singular or plural, are identified as they exist prior to cominginto contact with another substance referred to by chemical name orchemical type (e.g., another reactant, a solvent, or etc.). It mattersnot what preliminary chemical changes, transformations and/or reactions,if any, take place in the resulting mixture or solution or reactionmedium as such changes, transformations and/or reactions are the naturalresult of bringing the specified reactants and/or components togetherunder the conditions called for pursuant to this disclosure. Thus thereactants and components are identified as ingredients to be broughttogether in connection with performing a desired chemical operation orreaction or in forming a mixture to be used in conducting a desiredoperation or reaction. Also, even though an embodiment may refer tosubstances, components and/or ingredients in the present tense (“iscomprised of”, “comprises”, “is”, etc.), the reference is to thesubstance, component or ingredient as it existed at the time just beforeit was first contacted, blended or mixed with one or more othersubstances, components and/or ingredients in accordance with the presentdisclosure.

Also, even though the may refer to substances in the present tense (e.g.“comprises”, “is”, etc.), the reference is to the substance as it existsat the time just before it is first contacted, blended or mixed with oneor more other substances in accordance with the present disclosure.

Except as may be expressly otherwise indicated, the article “a” or “an”if and as used herein is not intended to limit, and should not beconstrued as limiting, the description or a to a single element to whichthe article refers. Rather, the article “a” or “an” if and as usedherein is intended to cover one or more such elements, unless the textexpressly indicates otherwise.

Each and every patent or other publication or published documentreferred to in any portion of this specification is incorporated in totointo this disclosure by reference, as if fully set forth herein.

This invention is susceptible to considerable variation in its practice.

1. An aromatic diimine wherein each imino hydrocarbylidene group has atleast two carbon atoms, and wherein said diimine is in the form of twophenyl rings connected by an alkylene bridge and having one imino groupon each ring, and in which each position ortho to an imino group bears ahydrocarbyl group, or wherein said diimine isN,N′-diisopropylidene-2,4-diethyl-6-methyl-1,3-benzenediamine,N,N′-diisopropylidene-4,6-diethyl-2-methyl-1,3-benzenediamine, or amixture thereof;N,N′-di-sec-butylidene-2,4-diethyl-6-methyl-1,3-benzenediamine,N,N′-di-sec-butylidene-4,6-diethyl-2-methyl-1,3-benzenediamine, or amixture thereof.
 2. A diimine as in claim 1 wherein said diimine is inthe form of two phenyl rings connected by an alkylene bridge and havingone imino group on each ring, wherein said alkylene bridge has from oneto about three carbon atoms, wherein each imino group is meta or pararelative to the alkylene bridge.
 3. A diimine as in claim 1 wherein saiddiimine is in the form of two phenyl rings connected by an alkylenebridge and having one imino group on each ring, wherein said hydrocarbylgroups ortho to said imino groups have from one to about six carbonatoms, and wherein the imino hydrocarbylidene groups have from three toabout six carbon atoms.
 4. A diimine as in claim 3 wherein said alkylenebridge has from one to about three carbon atoms, and wherein each iminogroup is meta or para relative to the alkylene bridge.
 5. A diimine asin claim 1 wherein said diimine is in the form of two phenyl ringsconnected by an alkylene bridge and having one imino group on each ring,and wherein said diimine has at least one of the followingcharacteristics: a) the hydrocarbyl groups ortho to said imino groupsare selected from the group consisting of methyl, ethyl, isopropyl,butyl, and mixtures of two or more of these groups; b) the iminohydrocarbylidene groups are isopropylidene or sec-butylidene.
 6. Adiimine as in claim 1 which isN,N′-diisopropylidene-4,4′-methylenebis(2,6-diethylbenzeneamine) orN,N′-di-sec-butylidene-4,4′-methylenebis(2,6-diethylbenzeneamine).